Any help here is appreciated...

Truck is stock except for aftermarket intake and exhaust system... (No tuner) I have cleaned the air filter (AFE aftermarket) replaced both fuel filters, cleaned the EGR valve... I can hear the fuel pump(s) cycle on...

Truck starts fine, idles fine (500rpm) but under load (acceleration) starts to missfire (around 1500 - 2000rpm). If I stomp it to the floor it bucks and misses then clears up briefly but then continue to miss. Almost like a pulse?

No codes are displayed... Is this a FICM problem? Could it be bad fuel? Never had an issue before I filled up at a new station a few days ago. Thanks for the help.

Oh, Forgot this detail: upon deceleration there is a low whistle or "air over an open bottle" sound. Where does this come from and is it related to the "miss"?

 

i went thru some of what you are describing. and i had to get it diag . and then they tell you what is going on. could be injectors. how many miles? did you change oil and filter? and what kind of filter and oil is it ?this is important check for chafing on the injector harness and glow plug lines. do this stuff before you take it in, may be monie out but still cheaper than getting into it.

 

Thanks for the response...

Truck has just hit 80,000. Changed the oil in her last month and put 15w40 in. No visible chafing on any of the inj. harn or gp lines... Gonna take another look to be sure.

Appreciate it.

 

you dont say what engine you have. the 04 can have an 03 engine from the factory.
if the icp sensor is in the right valve cover its a late build.
If its an early build then look at the icp sensor (behind the turbocharger) and see if its leaking some oil. common issue for 03/04 early builds

 

vgt vanes could be sticking not sure if this is a cause but just shooting you anything i heard
cheesit has a good point depending on what engine you have could be a few other things the guys on this forum are fairly knowlegeable so the advice is pretty good im just spewing some stuff ive heard so i hope it may help