I have been browsing several of your posts for a few days now and there seems to be alot of good ideas and troubleshooting methods floating around, so, I am going to throw a brain stumper at everyone and see what you guys think... I definitely need the help!

Ok, just bought a 97 F150 4.2L 6 cylinder 2WD, 5 speed. Has a little over 120,000 on it. I have had it for about two weeks now. Had been sitting unused for a couple months and it's got some issues, which I knew when I bought it, but didn't realize they were as bad as they seem to be.

After buying it, on the way home, it wouldn't get over 60 miles an hour, but a few miles from home, with my wife following me, I took off from a stop light and it backfired (the only LOUD back fire I have heard) and blew a brief burst of black smoke (The only black smoke we have seen) and was up to almost 80 by the time I got it home. It had been straight piped (Badly) when I got it, so it was pretty loud and smoking (white smoke). I was hoping some of the problems were from this. Got the exhaust patched the next day, and it stopped smoking AS MUCH, but, at times, it is still like a fog machine. Smells like STRONG exhaust, maybe a little gas... No oil smell at all to the fumes. Patching the exhaust just drew attention to numerous other issues.

1. When it is first cranked, has to be given ALOT of gas to crank. It is fuel injected of course, so, this should not be neccesary. Usually stalls at least once after it is first cranks, occassionally a backfire occurs, not really loud, but loud enough.

2. Idle is way too high, at times sounds like it is roaring.

3. There is some power loss, to the point where fifth gear is a joke, need to keep it in fourth.

4. Seems like it could be flooding itself out, but I was told that the fuel pressure is actually low. Which leads me to the next mystery... Where is the gas going? It is drinking it like crazy and you can almost watch the gas hand move.

5. There is a tap to the motor, seems to be coming from passenger side. It is too high in the motor to be a lifter I think.

6. Sometimes stalls on stops and turns.

Day after buying, looked it over and noticed alot of parts that have been changed by previous owners. New fuel filter, Drivers side oxygen sensor, and coil pack. Intake looks new or at least very clean, Air filter is fairly new, Sticker in door reads PCM/ECM work was done in December. Spark plug wires appear to be fairly new. Several other things have been changed, or cleaned. The previous owners were obviously troubleshooting...

Now for what I have done so far....
I took it to Auto Zone and had a diagnostic run. It threw 4 codes:
P0171 - Lean fuel bank 1
P0174 - Fuel too lean bank 2
P0500 - Vehicle Speed Sensor
P1506 - Idle Air Control Overspeed Error

Changed the bank 1 Passenger side O2 sensor, actually stopped smoking for about ten minutes after I put it in but then back to usual again. Changed the vehicle speed sensor and ABS sensor. Changed the oil (No milkyness to old oil, or antifreeze, so I don't believe this is a head gasket) I must admit I got a little irritated after no change, and it took me a few days to get back to it. My brother in law helped check some things and replace a few more things last night. I changed the PCV valve, ETC sensor, DPFE sensor, Spark plugs (which were all badly fouled) Cleaned MAF sensor and IAT sensors. In doing this, we noticed that half of the vaccuum hoses on the motor (passengers side) are not functioning when motor is cranked. and also the PCV valve had been gutted. After changing ETC and Spark Plugs there was not enough change to note. After cleaning MAF and IAT sensors same way. When DPFE and PCV was changed, Was able to crank without using the gas pedal ONE TIME, and it noticeably ran better although still not good. But the idle was so high it sounded like a jet taking off. Also, may mean nothing, but when I pulled the MAF and IAT sensors last night there were visible fumes trapped in the breather tube. Gave up for the night came back in, and hit the forums looking for suggestions and things to try.

Today, I performed a "suck test" on the EGR valve and it seems to be working. In taking the IAC valve off to clean noticed previous owners had done "something" with it, but cleaned it anyway and seems to have helped the idle a little but still too high. After resetting PCM last night, I took it back to AutoZone today and it threw 1 code - P0500, which I already changed last week. Power still sucks, needs gas to crank, still trying to stall. . OH YEAH....... No CEL light at all, even when it threw 4 codes.

The majority of problems seem, from what I have read, to point to an EGR problem, but tested fine, so, now here are my questions: Why isn't it showing more codes? Will EGR pass suck test if the ports are stopped up or the EVR solenoid is malfunctioning? How can it be going through gas like it is with low fuel pressure and no burning gas smell? Looks like previous owners have changed a screw in the throttle body (I believe it is the throttle positioning bolt). IAC valve has hex bolt at front, which shouldn't have been touched at all and has been totally stripped from previous owners trying to adjust the idle I am assuming... Can this be the whole problem? How does the fact that the cats have been totally removed on passengers side affect any of the issues I am having? Do the fumes in the breather tube mean anything? Could the PCM be on the outs?

Any suggestions you have would be great... I am open to suggestions at this point.

 

Just the one side???

The whole "I think they were troubleshooting" comment seems like a MAJOR understatement.

Here we go...Fix the exhaust system, replace the other o2 sensor, clean the EGR ports on the throttle body, the idiot messed with the idle screw? ...reset that to spec, replace the IAC, check system vacuum pressure/all vacuum hoses for leaks. That whole exhaust thing makes me laugh either cats or no cats so long as its the same for both sides LOL. I wouldnt even start the truck until all of this has been done personally. Cant imagine the EVR solenoid is bad...My truck has 140k and I've replaced the dpfe, EGR valve, and IAC valve. The EGR ports under the throttle body are probably FILTHY. I cleaned the EGR ports on mine for the first time @ 105k and they were a MESS. God knows what other crazy they did to that truck...GL

 

Oh, I also forgot to mention that the battery they have on it is too small (Doesn't come anywhere even close to filling the platform it is sitting on) ... Only 500 cold cranking amps, I have been told this truck should have 800 or more....

 

This is what worries me... I am seeing some strange things and I have a feeling that their "adjustments" are going to be a BIG problem. They actually had the IAC valve bolted down with one bolt that was way too long with 4 washers on it on one side and a sheet metal screw in the other side. I have never seen such crazy .

 

Okey dokey, you got alot of stuff at one time, let's see what we can do.

How are the brakes, do they feel like the booster is bad? Hard pedal, and check the vac line to the booster real good. Alot of what you have going on sounds like vac problems.

PCV-did you replace it with a Motorcraft? Also check the line from the valve cover to the throttle body for cracks/splits/burns. There is also a small rubber hose at each end on the PCV line that can rot/burn.

Next you want to check the IAC if it is gummed up then you have to give it some pedal to get it to start, this may also be the source of the high idle.

Now remove the air intake tube at the t/b and look at the butterfly to make sure it's clean. If not you might have to pull the t/b and clean it. Also see if there is any slop in it where the shaft pivots in the body, there should be very little to none.

You said that the vac lines on one side were not working? Did you mean they have no vac? If so this might be bad. But it could be that if the last guy tried to do the intake gaskets and did a poor job they could still be leaking.(the gaskets)

Get about a 2ft piece of vac line and stick one end in your ear and snoop around with the other end listening for vac leaks, If you find one fix it an needed.

I have 2 guesses;
1) The previous owner tried to do the intake gaskets and botched it, or did gaskets only and not the isolator bolts and that is where it is leaking.
or
2) If you have the plastic plenum it could be cracked.

Another way to check for vac leaks is using an un-lit propane torch and blow the propane around where you think it might be leaking. Do this with the motor running, if the motor changes rpm's you found a leak.

Sorry for the long wind and good luck.
Post up what you find out.

 

Brakes seem to be ok. What do you mean by "this might be bad" on the vac not functioning properly?

 

If you are not getting no vacuum off of the vac port on the manifold then you could have a very major leak or a crack in the intake. Have you put a vac guage on the manifold to see what kind of vac it is pulling at idle?

Also do you have the plastic or metal plenum?

 

opps, that slipped out, sorry.. Anyway, so you have converters on one side and none on the other ?

 

Sounds to me like that truck has been seriously afro-engineered.........

 

Go to the salvage yard and get the proper bolts.

 

you mentioned that you were getting codes, but no CEL on the dash...looking at the kind of "fixes" the previous jokers did, it wouldn't surprise me if they pulled the bulb for the CEL in the cluster so that there would be no light even if codes were present. pull the cluster to see if the bulb is there.

grab yourself a haynes or chiltons manual. I'd grab a volt/ohm meter too. check the sensors that you haven't replaced to make sure they are getting/sending enough voltage and/or resistance values. might as well check everything on that truck considering everything going on with it.

check entire vac system as mentioned above with ear/hose system and/or propane/carb cleaner around hose/gasket areas.

since there were fumes in your intake, sounds like your exhaust is backing up into you intake system

 

sounds like you bought a lemon. not to worry with a little bit of money your 4.2l will be up and going. My 4.2l sat in a barn in Mississippi for 8 years it was ran for 5 minutes every couple months and when they shipped it out to california and put it up for sale I bought it and it had no issues besides the bald tires. My issues just arrived last month though, My starter is going bad, my fuel pump isnt so happy lately even after changing the filter its pretty sad right now, and my flywheel needs to be replaced. but finding out whats wrong with you Ford is what this websites all about. Welcome to the site

 

Most definitely an understatement. I am appreciating all the feedback, although it is scaring me a little. I know it's a lemon... knew that when I bought it, but, for what I paid for it, I can invest a little and be under blue book. Just afraid it is gonna cost an arm and a leg.

But, yes, as far as I know, the converters are only off of one side. An issue all of its own. The plenum is metal. I will check for vaccuum leak, I knew I had one, just haven't found it. I know the IAC needs to be replaced for sure. Biggest problem is I don't know what problem to tackle first. There are so many things, it is hard to decide. The least costly ones would be my preference though.

 

Before you start throwing any parts in it, I'd advise you to pull the plugs and do a proper compression and cylinder leakdown test. If it looks good, then proceed and take care of all the crap it needs. If it's bad, don't even bother, go find a good used engine.

Just a heads up - the 97 and early 98 4.2's had bad intake manifold and front cover gaskets. If not replaced with improved parts, they started to leak coolant into the cylinders, eventually resulting in a hydrolock. You might want to do a hydrocarbon detection test on your coolant.

 

Whomever had that truck before you needs Chuck Norris to facepalm them. XD

You're probably better off taking the intake off, fixing things from there up, and taking the exhaust manifolds off, and fixing it from there back. You'll get a better view of the mess that way. Get a scope from harbor freight and take a peek in the cylinders, too, if you can. That's how I'd approach it, at least. Sounds like you have way too much guess work to do. Good luck!