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8.1L driveability problem...engine problem?

15022 Views 22 Replies 12 Participants Last post by  dionysos412
My '02 8.1L w/ 36k on it just developed a driveability problem.

Apears to want to stall when slowing to a stop (rpms go below 500) and sometimes feels like transmision isnt downshifting causing the truck to sorta want to keep pushing forward for a brief second.

Truck accelerates fine unless coming off of the stumble where it feels like a sudden acceleration from the brief delay.

Truck idles fine when in nuetral or park (no load).

Woried that it was a tranny problem....but fluid level is correct and looks good-red. I dont believe its been serviced yet...could a spin on filter replacement fix whatever is going on? Thought I may have read a while ago that that can cause driveability problems....

Problem apears to occure when warmed up...but cold out. Might be coincidence as it just started getting cold around here.

Does this sound like the infamous 8.1L crank sensor issue?

I'm gonna post similar message in Allison OEM in case its a tranny problem.
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Most people with the crank sensor issue complain about random stalling. That's what mine did. I also had the problem you describe. It required the TCM software to fix it. The message below describes what is happening. I snagged it from another post a long time ago. I don't remember where or I'd give credit.

What was happening is as you came to a rolling stop that the range selected, range attained and range commanded was being observed. When the trans made the down shift, the range commanded by the transmission computer was neutral and then came back to first range thus you felt the several second time lag when the unit came back to range.
mr_udy;1539987; said:
bilcar99: What size tire are you running? What year truck?

Thanks all for your help...I'll post what I find.

I am leaning towards the recallibration. BUT, I'm gonna clean my TB anyway...my old mechanical one on 5.3s always "coked" up...free service. Since I have'nt stalled yet, gonna save the crank sensor for last. By the way, where is the crank sensor? Front? Easy replacement?
I have 285's on it and it's a 2001. The crank sensor is on the back of the block, drivers side. It's a PIA to get out. It took me about 2 hours to finish it.
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