Its usually the pass side left coil pack that goes bad but since you changed your plugs 2 weeks ago,i would lean more towards a plug wire coming off..Go back and recheck all the coil packs removing one at a time.Then reinstall the same one at a time,Youll find out which one is bad

 

no, i haven't changed the plugs 2 weeks ago, the fuel filter was changed 2 weeks ago. the plugs have under 2,000 miles on them and were changed in fall, truck sat during winter, truck has been out of garage for about 2.5 weeks and running perfectly up until noon today.

 

Could it be possible you have a junk 02 sensor stuck on lean?

This would pour fuel in, but I would think it would throw a code as well...you didn't mention a check engine light.

I've had this happen twice, once lean & once rich.

Just a thought.

-Andy

 

i was going to autotap it tonight. i have an SES but i've always had an SES because of my egr hardware not being hooked up (the chip has egr-delete, but the vacuum controller (for lack of better term) wasn't deleted) i will check for other codes tonight.

 

I autotapped the truck...

No codes
No misfires

It's just running unbelievably rich all the sudden, and I have no idea why.

For anybody that understands this stuff, I have made an Excel file of a short data log. Maybe someone can see something wrong.

Click here to download log file (xls)

 

I would remove the chip, reset the PCM voltage, and drive it without the chip for a test ride.....................

For some reason(?), you may have a fuel injector stuck open/on???

Also check for an extremely dirty air filter..................

Dan

 

yeah, tonight i was going to mess with chip/pcm