My girlfriend owns a: 1991 Nissan NX 1600 1.6L (about 85,000 original miles)
So heres the rundown. Her car was running however it was running rough and didnt seem to be shifting gears properly. The shift from 1st to 3rd resulted in a really hard shift. So much so that the tires would break loose a little. So like a good boyfriend i decided to try a tune up to see if it would help the car to run a little smoother. Went to the store and bought plugs, cables, cap and rotor. Came home and installed the new parts. Spark plugs were exactly the same as the plug that were already in the motor while it ran. Finished up everything then decided i should check the compression on the cylinders because the mechanic said it seemed like the vehicle was running with only 3 out of 4 cylinders. The compression check when well and results were perfectly normal. Then i jumped in the car and went to start it up. Ofcourse, im excited about the new parts and...the car started, idled inconsistently for a few seconds, the rpms seem to jump a few hundred then it died...this was about 3 weeks ago.
Alot has been checked, replaced, checked and checked again...each time i end the day completely stumped. So heres the list of things ive done over the past couple of weeks.
-found out cylinder #2 had a bad fuel injector and i replaced it. This explained why the car was running rough for the past 2 years.
-then i figured out that if i disconnect the MAF sensor the car will idle low (about 500 rpms) but consistent. i can also rev it up to about 2400 rpms before it seems to bog out and will not accelerate past 2400 rpms.
-ive tried resetting the ECU various ways with no noticeable change.
-i replaced the fuel regulator valve, with no noticeable change.
-i replaced the mass airflow sensor, with no change at all.
-cleaned the throttle body
at this point i am completely stumped and have no idea where to go next. If anyone knows anything about a similar issue and could offer some words of advice, i would greatly appreciate it. anything at all will help
Thanks in advance!