I have a 2000 d2 that has decided to start idling rough when it's all warmed up. The engine light doesn't come on (it does work trust me) but the computer is storing a p0100 code. I tried cleaning the maf and while it did seem to make more power the code is still showing up. I ended up replacing the maf since it its almost 200k miles old. Makes even more power but is still having the same problems. My code reader can see the maf and the data the computer is reading so at least the connection is good. Any ideas what I should look into next? I cant seem to find any info on this site with that code.

 

Apparently P0100 is a generic powertrain code. Have you been able to at least temporarily clear the code with your reader? You may also want to see if another scanner registers the code. Your rough idle may be caused by other issues.

 

Post your fuel trim data. Long term and short term. I would not do anything further until you know if your ECU is adding or pulling fuel.

Have you ever replaced your purge valve?

 

Coors- what is considered proper fuel trim?
1) At cold idle
2) Warm idle
I have asked this question before but no one wants to pony up an answer.

 

I will get that up from my drive to work. I remember taking a glance at it and I think the long trim was 12% but I will double check. I haven't replaced my purge valve. not really sure where that is on this truck.

 

I can clear it but it usually comes back. odd that it never causes a check engine light. I will try and grab a friends reader and see if it shows the same code

 

I have swapped MAF's out on D2's without having any issues (all were running good with no codes). Then I've replaced them on bad running D2's (bad MAF), and usually slapping in a brand new MAF did not fix the issue until I had the adaptive settings reset.

Then after that they ran fine. I had one D2 that would run fine with it's INOP MAF, but whenever you installed a new one it would idle high, and run rich setting off all sorts of O2 related faults. I was able to get it to relearn on it's own after just driving it, but it took a long time, and it was kinda hard to drive in stop n go traffic with the high idle. I had to use the brake a lot, I had no choice at the time as I was out in the middle of no where (thank god I had a spare).

 

How and where did you get the adaptive settings reset?

 

ok i grabbed my trims. for what ever reason my reader sees it as 4 different banks

"cold" 100deg water temp openloop
short trims
b1 0%
b2 10%
b3 9.4%
b4 18.8%

long
b1 -1.6%
b2 0%
b3 8.6%
b4 11.7%

warm 189% <- average temp for me with 180 thermostat
short
b1 1.6%
b2 11.7%
b3 10.2%
b4 21%

long
b1 -3.9%
b2 -2.3%
b3 6.2%
b4 9.4%

I will say it did idle a little better today. it went from feeling like multiple misfires to maybe a v8 running hot cams

 

It has 4 readings for 4 dif't sensors. 2 pre-cat, 2 post cat. Ideally, fuel trims fall between 2% and 3%
Did you buy a Bosch MAF sensor or a cheap knockoff? You want to go with Bosch on any of the sensors; aftermarket sensors cause more problems than you started with, sometimes! Could be a faulty upstream Oxygen sensor but without a hard fault code you can't be for sure without stringing together some other data or running a sophisticated OBD hardware on it. Maybe even a vacuum leak; test for that with smoke or vapor real quick as it's free & easy. Intake manifold, brake booster, SAI valves, etc.