CHEVY IDLE SURGES UP AND DOWN AND BOUNCING OI

1991 Chevrolet Cavalier

Tiny

sean_zacker

November, 19, 2009 AT 11:41 PM

Engine Mechanical problem
1991 Chevy Cavalier 6 cyl Front Wheel Drive Manual 130000 miles

i have a 1991 cavalier has a 3.1 v6 5 speed when the car is idling it idles up and down only sometimes and when the idle drops down and then back so does the oil pressure idk changed the tps and iacand no change almost like the engine is surging also has a miss only at idle cant find a vaccum leak anywhere

5 Answers

Tiny

mmprince4000

November, 22, 2009 AT 7:51 AM

Got to be a vacuum leak somewhere, IAC is attempting to compensate but can't because of leak.

Tiny

sean_zacker

November, 22, 2009 AT 8:36 PM

I have checked all over I can here like a pss pss sound but might be the exaust cause its not all the way tight at the flange

Tiny

mmprince4000

November, 23, 2009 AT 7:02 AM

You can spray carb cleaner at suspected vacuum leaks, any change in idle is where the leak is.

Tiny

sean_zacker

November, 24, 2009 AT 12:30 AM

Ok I just did that and found nothing I need help

Tiny

mmprince4000

November, 24, 2009 AT 7:22 AM

You need a scanner that can read live data. Watch the movement of the IAC (called " steps" ).

Most shops can generate smoke that will migrate toward the vacuum leak.

You could try a compression and cooling system pressure test.

But it could also be a leaking injector seal, intake manifold gasket.

Also scan timing advance.

Please login or register to post a reply.

Vacuum Leak Test and Repair - All Cars
Clean Idle Air Control Ford Super Duty 5.4L
Easily Clean Your Throttle Bore Like a Pro
Code Read Retrieval/Clear Mercedes-Benz C230