2000 5.4 130k miles. Im not exactly sure if this is what is causing a bogging issue im having or not. Heres the run down. at 125k I blew a head gasket, got it all changed, new MC plugs. Well I kept getting a lean bank 1 and 2 code. So I sent my edge in and got a Gryphon with a custom tune 93 performance to run b/c I thought maybe shaving the heads and headers I installed may have been causing it to run lean. Well even after that it seems every now and again ill get a lean code. Well the past month i've had number 4 and number 8 coil packs go out, both changed. Now it seems that temps are rising my truck has a bogging issue like you cant feel it in first but as soon as it shifts into second and rpms drop it is a freaking DOGGG building back rpms. like if im cruisin at 35,40 give it some petal. shifts out of over drive it feels like a pulling a freaking trailer. Now, im gonna take it for a ride here in a second now the temps are coming down and see if it is the heat causing it or maybe something else. But i havent cleaned the MAF before and i was thinking could that be it? Also more info at about 90k I changed the passenger side o2 but I code came up telling me, no code this time. What do you guys think it may be? Im trying my best to give you guys a good description but its hard. When my coil packs went bad and it missed you know how it feels like its not going anywhere well it KINDA feels like that, but no miss and I believe, i will update my post when i get back its only like between 2k-2500?? rpms. Ill do a couple runs, normal cruise, down shift cruise, WOT from a stop and see what I can figure out. Just give me some ideas what it sounds like fellas.

 

If the computer thinks it is lean then it will richen it up. An exhaust or vac leak will make the 02"s show lean and cause it to have a fat a/f ratio. The air leak makes it look like it is lean.
sooooo if you ran very long with the "lean condition" which was actually rich then you could have damaged the cats. Clogged cats will make it have the symptoms you have. Add to that having 2 coils go down that is just that much more raw fuel into the cats.
Now add to that the history of a blown head gasket-cats hate coolant.

My thought would be look at the exhaust system and check for back pressure.
Good luck.

 

question... how do I check the cats? I need my emissions done by june 9th, will that show if they are messed up?

 

After you try to run it hard look underneath if they are glowing then they are cooked. Or if you open the headers and take it for a SHORT spin and it runs much better, then it is probably cats.

Don't know about Maryland but out here on the left coast it would cause a fail-Sorry hope that isn't it.

I take it the test drive didn't go well?

 

im waitin for it to drop alot more haha. wouldnt cats taking a dump make my fuel mileage drop a ton? It hasnt changed the slightest, but if it fails ill get an extension... well MAYBE haha i dont know what will happen hopefully they wont take my truck off the road or something. But ill run it around for a few miles and see if they are glowing or anything. Can you change a cat? arent they welded on and if in fact this is the problem guys what do you suggest I do haha. what style cat? will putting one high flow on each side throw any codes instead of having all 4?

 

Yes you can and yes they are.

 

Is there anyway to tell which cat is bad, im guessing it will be the one red hot?? I dont know much about the cats but can you only go with 2 high flows(1 on each side) and have the o2's not throw any codes?

 

well... outside temp 72 F, coolant temp at start 120 F, then in about a mile or so normal 190+ temp. NO SIGN OF BOG OR SLUGGISH BEHAVIOR WHAT SO EVER and cats were not red at all. I mean not even the slightest sign over unnormal tempature. WTF is going on I know its got to be something with this hot muggy air guys but what. Damn I know my racecars will slow up a couple tenths but you cant feel it like you can feel this. I mean I did a 20% throttle, it shifted rpms dropped way down and eased into the throttle just enough where it wouldnt down shift and it pulled all the way through. WOT until 80 mph even a slight up hill angle and it pulled great. Could it be the MAF, or air filter? Im puzzled

 

I noticed I didnt add I have a the k&n kit.

 

Well have you cleaned the MAF yet? It wouldn't hurt. And the K&N can get the MAF oily.
The other thing if it seems to be temp related you might pull and clean the IAT, it's in the intake tube also. If both of these are oily that could throw the fuel metering off.

You got me guessing too but glad it isn't the cats!

 

if your hoping to have huge power increases in summer weather you're wrong, expecially with a hot air intake under the hood

 

im not looking for any gains, haha I just want normal behavior!! so you dont think there's anything I can do?