5.4L running very rough details inside.

[Gegecat911]

99 5.4 have replaced plugs, coils, MAF, fuel filter, Cleaned egr/tb. Checked fuel pressure ok at 37psi. Unplugged each injector seems to be working properly. Loss of power on take off shudders bad on highway. No cel or codes checked with multiple diagnostic computers no issues found. Measured temp of cat's bank 1 and 2 same temp.

Runs bad 80% of the time, other times normal. I'm at a dead end here with no codes popping up. Thought it was fuel related checked everything seems ok.

Any ideas or others with a similar problem in the past? Any ideas would be appreciated.

 

[1997SCEBFEX]

You say you checked ALL fuel components; when/where was the last time you purchased gas? How about your CATs or a broken wire(s) on one of your injectors?

Le us know what you find.

 

[walnuts4x4]

I know you said you changed COPs but I'm gonna say you have a low grade missfire out of one of them.... its a classic symptom you are describing... also when I changed mine I had one go bad the same day it was installed and no CEL... took it to dealer and they did a powerband test and found the culprit... bad COP

other option would be check this link

http://expeditionforum.com/showthread.php?t=4926

 

[Gegecat911]

thank you both for your responses. when i unplug each injectors you can tell its working because it starts to miss right away

 

[Gegecat911]

i changed the coil packs after the problem started with new ones, still same problem im asking you guys for ideas before i take to dealer i work for honda dealer been working on cars for 14 years but still i'm at a loss with my own car lol.

 

[Gegecat911]

i bought cheap gas but have since refueled with 93 and injecter clean but still same crap

 

[Gegecat911]

i might have to be robbed at dealer for check up it seems I'm out of ideas

 

[Gegecat911]

and i can't drive much longer like this. My truck is my baby if anymore ideas please feel free to post them thanks a lot. I checked the vac line it was ok.

 

[Gegecat911]

Finaly got cel its says random missfire

 

[Gegecat911]

Just an update. Walnuts you were correct. Brand new Coil on #6 and #8 were both bad. Replaced and the truck runs great now. Checked each injector and and coil with a Snap on tool for each. Put a stethoscope on each injector to actually listen to make sure it was function. After eliminating all possibilities I got two new COP's from the dealer and moved them around 2 at a time until I found the faulty ones.