@kcward;

I don't buy that "new engine" BS that the "stealership" and everybody else likes to put out on the 5.4L 3v engines. They outa' go 450K miles+ just ****tin & gettin'. My '04 5.4l did have a "plastic" manifold crack at about 200k mi. that caused out of whack fuel trims, bad gas mileage, and several screwy codes, including P0430. (was clearly detected by spraying "starting fluid around the intake manifold while monitoring O2 sensor graphs with Torque Pro App). It was a real bitch kitty to replace (especially the brake booster vacuum line on the rear of the intake manifold). But there is another, fairly flimzy vacuum line connection that supplies vacuum to the vacuum-compensated fuel rail pressure sensor that attaches on the lower passenger side of the intake manifold. Then, all that crap affects the intake manifold (C)harge (M)otion (C)ontrol (V)alve located on the back of the intake manifold!

But now I'm north of 200K miles and I am also experiencing (intermittent) rough idle. I believe the source of the rough idle is either from imperfection in fuel injector flow - OR imperfect variable valve timing operation. I think I may be facing Cam phaser replacement and I am interested in your rough idle issue. I have expended considerable effort in isolating four (4) custom parameter IDs (PIDS) that the PCM maintains relating to the Variable Valve Timing system operation (Cam Enable), (Requested Retard), (Solenoid Duty Cycle), and (Cam Error). If your scanner can read live OBDII date, I can provide you with these four PIDs and I would be very interested in comparing results.

 

The "other fairly flimsy" line is what I was looking for... I had my hand jammed behind the intake feelin around... I have only found one picture/video that shows it...I know it's a long shot...

I keep tinkering with it, and nothing makes a difference...

Until I come up with some $$$ I'm gonna keep driving it...

 

So, its been about 4k miles since the new engine diagnosis...

I have been driving it...it just passed smog...if y'all can believe that. Fortunately, they are doing the OBD smog checks now on vehicles newer than Y2K...I think if it were the old Dyno/tail pipe test it wouldn't have passed...I removed the GOTTS O2 mod before taking it in, so It would pass visual...and was praying that the P0430 didn't show up before or during the test...It still hasn't given any codes in 4k miles...it just runs rough...

I gave it a break last month...took my girlfriends Mountaineer to Scout Camp in Oregon...a 900 mile round trip...Its the first camp my truck has missed since I have had it...but I did take it on another scout camping trip to Lake Almanor (400 miles round trip) last weekend...it ran good, and got a record 15mpg on the trip...truck had 3 passengers and a bed full of Scout Gear!

 

Have you checked for vacuum leaks by spraying starting fluid (or something similar) around the intake like F150torqued suggested ? With your scanner, watch the O2 data streams and see if they jump around when you spray the starting fluid.
Are the O2's original? They can get lazy after 50 or 60k miles and report false information to the pcm.
You may want to also check the compression yourself. A compression testor isn't expensive, and the test isn't hard.

 

I have checked for vacuum leaks using starting fluid...nothing that I could find......

I haven't tried a compression test...I don't have the compression tester, nor the special fitting for the ford spark plug...

It seems to have too much power for it to be a compression problem...especially for 3/8 of the engine supposedly bad? I am kinda leaning toward a misfire...but I can't track it down...I have replaced several of the coils these past few months...BWD's from O'reilley...

2 days ago marked 10 years of ownership...had 18 miles on it when I bought it...now at 179,460...

 

Any updates to your truck's issue? I think we have a very similar problem, that's why I'm asking. Sorry for the long post... but it might help you some.
About 10-15 days ago took my truck in to have the tranny pulled to replace the flexplate. The flex plate had a couple of chewed up teeth and every now and then the starter wouldn't work as it should, due to lining up to the bad teeth. Anyhow when I got the vehicle back, it had developed a rough idle, when under no load. Almost like the timing was too advanced, (if you remember the days of timing an engine by ear, turning the distributor). Seems to run okay when driving around even on the freeway and have put about 1500 miles or so on it, since the tranny was pulled. Oh yeah I had them replace the torque converter, while the tranny was out, as I thought it was acting up. No codes of any kind either. At first I thought the engine was out of balance... but I'm just not sure.
My vehicle is a 2005 Expy w/ 5.4l 3V with about 130K. I bought the vehicle about 40K miles ago and have been good about making sure the maintenance has been done. Changed plugs at about 95K miles, replaced the COP's about 10K miles ago, changed the fuel filter about 3K ago.

So far on this issue, I have cleaned the throttle body, checked for any kind of vacuum leak with carb cleaner, (vacuum gage is steady at idle too). I've even checked the motor mounts, and they are fine. I have swapped out all of the COP's just to check, and now I think I'm up against either changing out the spark plugs and possibly changing out the fuel injectors... not sure what else to try. Any advice would be welcome.

By the way I hope your not still considering the CAT as part of your issue. Every CAT I have replaced, the symptoms were that the engine would reach a certain RPM and no more... the engines would run okay just no RPM/power. So I don't think bad CAT's are your issue.

Thanks and again sorry for the long post.

 

Hey Rocket!

I am not still considering the Cats...I am going to look at the fuel injectors, or still searching for a vacuum leak...

I have a code scanner that gives live data...the fuel trims are way off...bank 1 is running way lean according to LTFTRM at around 17...Bank 2 hovers around -3 to +3... (that is if the info I have read is correct with lean conditions being +, and rich being -) I have tried using starting fluid to check for vacuum leaks with no success. I was looking at the engine the other night (scratching my head and wondering what I'm missing)...#3 injector has alot of dirt around it, and I am wondering if this is the cause of the vacuum leak. Its way dirtier than all of the others, and its newer than the others as it was replaced at 81k miles...

Sorry for your problems!

 

KC,
Sounds like you're starting to get somewhere, or at least narrow it down to the passenger side. I need to get a scanner that provides live updates, my current one does not... any recommendations? It would be nice to see what's going on with the fuel trims.

Doing a little more research, I found the F150Torqued did a great write up on a floating miss... gives me some more to check out too.
I really liked his idea of the carbon left over in the engine after you remove the spark plugs, being a contributor to the shorter life expectancy of new plugs. Looks like I'll pull the spark plugs, inspect them for anything "odd" and get a small steel round brush to clean out the area inside the heads. Gotta be worth taking a look at least.

Also, if you have access to a laser temperature probe, F150Torqued brings up the point of checking the temperature of the CAT on the lean side... maybe you have some injectors dumping in too much fuel, trying to make up for some borderline injectors. The CAT temperature should help with that. Too much fuel usually indicates a higher CAT temperature, but if you have some borderline injectors being covered up by others on the same bank dumping more fuel, the CAT temp would be normal, or maybe even slightly lower than normal.

By the way I read injectors should have an electrical resistance of 11 - 18 ohms. All of mine checked out between 13.4 and 13.7... or course that wouldn't help with a leaky one, but it was something easy to check.

Just some thoughts.

 

I can also see Cat temps on my scanner...both are generally equal to each other +/- a few degrees... I do know that the drivers side Cat is bad...I have been getting P0430 codes for several years. But it/they are not plugged... I did the gotts O2 mod...I haven't gotten a P0430 code since doing it...(except that I removed the mod last month so I would pass visual on the smog test, and haven't put it back on. I have gotten 3 codes in about 700 miles...). I did pass smog last month which is a joke now...they just run OBDII, and a visual...if no codes you pass...

 

Have you replaced the O2's yet? I'm generally not a fan of replacing them just because you get a code, however, 176k miles is a lot for original sensors. It would suck to chase this problem all because one or more O2 is reporting false data.

 

Hey guys gotta question... hope it's not too silly.

If your engine runs rough, but doesn't produce any codes... I'm curious about the O2 sensor thing.

I fully understand that O2 sensors can get slow to respond at about 100K miles and such... but if your engine is running slightly rough as mine is, when you first start it up, (or within a very short time) wouldn't the system be in open loop?

So I guess what I'm poking at is if the PCM accepts input from the O2 sensors during open loop operation? If so then I'll accept the O2 sensors being a cause for a rough running engine, (when it first starts). If not then...???

I honestly don't know.

Thanks guys.

 

I think you are correct - but to be clear - "If the PCM 'thinks' there is a lean condition (there's the clue), based on O2 sensor readings, it adds time to the injector pulse width (FTRIMs "+") in response. IT seems, at least in my pea brain, a "+" FTRIM reading is rich, but I know what you meant. Many aspects of he OBDII system and its readings seem upside down, like the O2 sensors. Does a .9v reading mean "rich" in fuel ratio - or "rich" in oxygen (which would be opposite)? Took me forever to figure that one out. Only did so with my Torque app - IF I FLOORBOARDED IT (completely out of closed loop) the O2 signals would go High. (guess that means .9v means rich - IN FUEL). lol


Anyway! Your scanner indications would confirm a P0430 code because the front CAT will get "swamped" with excess fuel which it cannot burn off fast enough to satisfy the OBDII's continuous, real time "rich to lean voltage" and "rich to lean time" catalysts effeciency tests. These are determined by comparing readings between the Front O2 and Rear O2 while the PCM (intentionally) diddles with fuel trim for this purpose.


Have you considered an Exhaust leak ahead of the front cat? Do you have the signature "tick" that seems common on 5.4l bank1 manifolds? In that regard, the cam retard is used for EGR effect, and during high retard conditions sucks exhaust back (aspirates) exhaust back into the cylinders and this could be pulling raw oxygen into the exhaust manifold ahead of the front O2. Also, Freeze Frame Data (stored at the instant a DTC is set) might tell you something more about WHEN the 0430 code is set - ie: off idle, at low-mid power, higher RPMs, or on deceleration, when retard is maximum.


Just some more avenues to explore. Hope it helps


PS - Just in case you suspect an exhaust leak -- another cleaver and inexpensive test that I just remembered reading about: Fashion a Shop Vac hose (pressure side) to the tail pipe with duck tape, and use soap spray bottle looking for bubbles! If you can't reverse the Shop Vac hose, you can use the trick anyway and listen all around using a piece of 3/4 heater hose for a stethoscope listening for a hiss or whistle. I am a strong advocate for CHEAP diagnostic ways and tools.

 

@ rocket_man


You are correct, the PCM ignores input from the O2's during open loop, and injector pulse width becomes some "default" value - probably from some table similar to the fuel trim tables, driven by MAF, RPM, engine load and the like - all at the complete expense of catalyst efficiency and fuel economy. I USED to think old or deteriorating injectors could contribute to light rough idle. (That feeling that our engine is out of balance). But one night while staring at the ceiling pondering the operations of the internal combustion engine, I had a couple of revelations.


First - the amount of fuel injected under a given condition, doesn't have much (if any real) impact on the explosiveness of the individual combustion processes. What does is the amount of air - discussed second here. Instead, excess fuel would only raise the "lambda" or ratio of unburned fuel in the exhaust. ie: all the fuel above 14.7:1 doesn't get burned up. Hence the need for CATS. Too much less than that won't ignite resulting in a "miss fire" which we aren't witnessing.


Second - however, the amount of air aspirated is critical as evidenced by how little acceleration it takes to increase RPM significantly. Remember the old "idle jets" days. A VERY slight increase or decrease in air intake dramatically changes the aggressiveness of the internal combustion process. And THUS, possibly enough to be felt in the engine shaking.


What could cause this? My 5.4L has the famous "lash adjuster" TICK. Analyzing that I find the Roller Follower has a cantilever design - (The Lash Adjuster forms the pivot point, the Cam Lobe presses the roller-follower in the middle of the follower, but nearer to the lash adjuster end than the valve stem). This creates an approx 2 to 1 leverage advantage. I found some 5.4 specs: Cam Lobe Lift = .217", Valve Lift @ 0 lash = .437". The factory spec states @ 0 lash. With the cantilever effect at 2x1, a lash adjuster length loss of.05" would be a .1" on the valve opening - and so on.

Could stuck / sticky / leaky / "TICKING" lash adjusters be effecting the cylinder aspiration due to "valve lift loss" under low rpm, low oil pressure, high vacuum, idle condition. It darn sure goes away as soon as you come off idle?


OK, Everybody's Thoughts.... I'm ready for my head bashing .

 

Ok...so my little experience in Water and Wastewater instrumentation would tell me...

An Oxygen sensor is built to detect Oxygen...it outputs a signal based on the level of oxygen...so, I would assume 0= lack of oxygen, and +0.9 would be the presence of more oxygen...typically the pre O2 sensor is bouncing around real fast but typically in the lower end...the post O2 is hovering around a 0.6...but changes....my passenger side post changes as fast as the pre...hence the P0430 code...

Funny thing is that O2 sensors are used in Water and Wastewater treatment...they have to be calibrated all of the time...monthly usually...how can a sensor be subjected to such extreme conditions on our trucks without routine calibration?

Food for thought! Thank you guys for all of the suggestions/advice!!

 

Below a fuel mix of 14.7 air to fuel ratio, there shouldn't be any oxygen. Oxygen is detected if the fuel is leaned out to a higher ration than 14.7. I'm talking stuff I read years ago, so don't trust me too much.