2002 SSEI with a L32 engine swap. Currently at 167K
History, everything has been running well for about 40k and well over a year after the swap. after figuring out a few other minor issues. Then the MAF went bad about a month ago. replaced it with a cheap one I had laying around and that seemed to fix everything for about a month. then while going home one day the transmission just out of the blue acted up and started shifting hard disabled the traction control and acted like it just was slipping some. Had a local well respected transmission shop check it out and they said it was worn out and the computer could no longer make up for the wear and I needed a rebuild.
So we rebuild and do some tune mods to the shift timing and TC lockup speed. Running great for about 2-3 weeks then I start getting P0420 and rich codes and it acts like I have a misfire, but no misfire code. Take it to the Mech shop and they run diagnostics on it and say it's running rich and that's causing the rough idle and running like a misfire. We all agree at this point to reset the ECM back to factory settings. Recheck diagnostics and everything looks to be fine. Head for work the next day and cruise set at about 72-73 pulling a long semi steep hill the transmission starts IMO unlocking the TC and then down shifts the shifts up then then down shifts and acts like it's misfiring which at this point I kick off the cruise and takeover. It does the same thing on the next long semi steep hill. See Video at https://drive.google.com/drive/folders/ ... sp=sharing
So I take it back to the transmission shop and tell them what it's doing. They agree to check it out. They drive it around town and then agree to take on the same run I did when it was acting up and they tell me "The trans is working fine. It's surging at certain loads. It's setting the P0420 code which may be a result of raw fuel going down the exhaust pipe." They now want to talk with the mechanics shop and take it out for a drive together.
So after about a month of me not having a car and shuffling it back and forth from the mechanic to the transmission shops. We are no farther along than when I took in to the transmission shop to begin with.
Could my computer be going out or is this some sensor feeding bad information to the PCM. (I did a fuel pressure test and it was about 42 PSI and after I shut the engine off it drops to about 38 and then raises to about 50 and holds) so I don't think my injectors are leaking. We've check the pressure regulator and it seems fine. New plug wires.....etc. and again it feels like a misfire, but it's not throwing a misfire code and it is definitely causing the transmission or PCM to act up.
Has anyone ever experienced anything like this before? the only codes that it has thrown thru this whole thing is the P0420, P0172 and the transmission code that resulted in the start of this whole thing.
Forgot to mention that the transmission shop told me that when I originally took it in they thought it was running lean and it was probably because of the GenV blower which led to the the PCM mods they done. I had randomly gotten the P0420 code every since the engine swap but it only seemed to come up once in a great while and it seemed to appear more during hotter summer months and not at all during the winter months. After I replaced the temperature sensor in March I don't think I had gotten the P0420 code at all.
At this point I feel like
Update:
Talked to the transmission guy and he was able to duplicate the problem and said the transmission is fine. Very little slip on the TC PID and all the other appropriate trans PID's. He says it's a result of being under powered. So we are thinking it's a timing advance or something along that line that is messing with the spark, fuel timing when at the higher rpm's and heavier loads.
Does anyone know what the timing advance should be at around 3000-3200 rpm? Other than a scan tool, how do I know if it's correct?