Terry in Va Beach
New Member
I unplugged the EFI fuze to reset the trouble codes and increasedthe idle by rotating the the throttle position sensor (TPS) clockwise. It now idles fine with no stalling. However, the cars is missing as I slowly accelerate as well as pinging at lower rpm especially during acceleration, so something is not right. I trhink it is still operating in the fail-safe mode. Trouble shooting according to the book, is first to replace the MAF. If that doesn't fix it (new part is $1000 so if anybody has a good used MAF for a 1990 LS400 for sale let me know?) It just seams that there arre no moving parts in the MAF to fail. There are a lot of sensors going into the ECU. Anybody have any ideas. Perhaps O2 sensors? (4 in all). Unlikey the majority of them failed but car is 15 years old with 175K miles and perhaps most had already failed.