05 Eddie 5.4 3-Valve-No power

[Grant]

Hello all.

I am at my wits end on this one. I purchased this truck about 2 months ago and almost immediatly noticed a lack of power. When you punch it, it will down shift and rev but goes hardly nowhere.
Here is what I have already done:
Replaced all spark plugs.
replaced Fuel filter. COP's all checked out.
No change so i took it to my dealer and they replaced the #7 injector (under warranty) but solved nothing.
They told me that the #7 compression was way down and wanted $4,700.00 to fix it.
I said goodbye and went to my local mechanic who then compression tested all cylinders. Well, they were all off quite a bit so i scheduled a valve job.
Valve job completed. Motor probably was over heated at some point.
Still no change.
No fault codes and my mechanic is at a complete loss. All I ended up paying for was the parts and the machine shop but I am still set back almost $2,000.00 with no end in site.
Called 3 dealers today and they all are basically telling me they have no idea and would need the truck (and my wallet) for an extended period of time.

Any help or direction would be greatly appreciated.

 

[Tigster]

dumb idea but possibly a clogged cat?

 

[Grant]

Had it checked and the back pressure checked out. I also changed the Fuel filter just in case.

 

[Stoned06]

How many miles? Did they recheck compression after the valve job? Possibly bad rings if still low. Have you had the tranny checked out? Does the engine rev OK in Neutral? I'm pretty sure in Park there is a rev limiter, but not sure about Neutral. If compression is now good, and the engine runs OK in Neutral, then I would suspect tranny.

 

[WHOISMOOTOO]

x2 on trans, does it slip or just no power?

 

[Grant]

Tranny seems OK but it does rev weird in Nuetral. If you hold it down (gas peddle), it revs up and down to about 3000 rpm not above. Not sure if it has a rev limiter that would cause it to do that.

Compression is ok now after the valve job.

Im gonna go after the TPS (throttle position sensor) and the MAF (Mass airflow meter) today.

Another thing is when you clear the computer history, it runs good but as soon as it shifts, it goes back to running like crap.

Another thread had someone saying that the cause was the gasket, air was sucking past the plenum.

BTW, 80,000 miles on this 2005.

 

[Stoned06]

Tranny seems OK but it does rev weird in Nuetral. If you hold it down (gas peddle), it revs up and down to about 3000 rpm not above. Not sure if it has a rev limiter that would cause it to do that.

Another thing is when you clear the computer history, it runs good but as soon as it shifts, it goes back to running like crap.

BTW, 80,000 miles on this 2005.

I believe that would be the rev limiter when not in gear. I would be worried about "as soon as it shifts it begins to run like crap". I would definitely take a look at the tranny.

 

[huklebuk]

Could b the pcv valve and elbow. if the leak it can cause all kinds of weird probkems

 

[ELVATO]

If you shift it to 1 or 2, it locks it in those gears. Does it drive normal or loose power in either of those? How about turning off O/D?