Been having idle issues for a couple of months with my gli 4g15. Revs will bounce by about 100rpm at idle, itll sit at 1000rpm then suddenly drop to 800 then go back to 1000rpm after accelerating. There is also a rattle from the front of the engine (one bolt holding the ac /p/s assembly to the block IS missing), and a very slight misfire at idle. Mechanic didnt think the rattle was valves or anything internal. There is no CEL. Car is always run on 95
Things i have done to try fix:
New dist cap (forgot to mark before taking of and wasnt put on in correct position. didnt affect anything. engine ran the same)
New dist o ring
New spark plugs
New ignition leads
New Fuel filter
New p/s a/c belt (still need to change alt belt)
New tb
Tried 3 different ISC
Checked TPS voltages (0.9 and 4.8)
Cleaned throttle body and intake (no gap around butterfly valve)
Injector cleaner (wynn's)
Valve cleaner (wynn's)
Tested PCV valve (air goes one way)
None of that worked and issue remains.
Had ignition timing checked and adjusted (was on 25 degrees) Changed to 5 degree as noted in service manual.
Since i had the ignition timing adjusted, the car has no or very sluggish acceleration below 3000rpm. Even a slight hill in 3rd at 60 with foot flat to the floor and ill still lose speed. Other issues remain.
What ive done since adjusting ignition:
Replaced most vacuum hoses (got brake booster and purge solenoid lines left)
Things to try:
Ill be rechecking the tps in the morning to make sure it is still set right.
I do also have a new o2 sensor. is it worth swapping it out?
Test purge solenoid
What else could be causing the issue with the acceleration?
Things i have done to try fix:
New dist cap (forgot to mark before taking of and wasnt put on in correct position. didnt affect anything. engine ran the same)
New dist o ring
New spark plugs
New ignition leads
New Fuel filter
New p/s a/c belt (still need to change alt belt)
New tb
Tried 3 different ISC
Checked TPS voltages (0.9 and 4.8)
Cleaned throttle body and intake (no gap around butterfly valve)
Injector cleaner (wynn's)
Valve cleaner (wynn's)
Tested PCV valve (air goes one way)
None of that worked and issue remains.
Had ignition timing checked and adjusted (was on 25 degrees) Changed to 5 degree as noted in service manual.
Since i had the ignition timing adjusted, the car has no or very sluggish acceleration below 3000rpm. Even a slight hill in 3rd at 60 with foot flat to the floor and ill still lose speed. Other issues remain.
What ive done since adjusting ignition:
Replaced most vacuum hoses (got brake booster and purge solenoid lines left)
Things to try:
Ill be rechecking the tps in the morning to make sure it is still set right.
I do also have a new o2 sensor. is it worth swapping it out?
Test purge solenoid
What else could be causing the issue with the acceleration?