1991 Chevy Cavalier 1991 Cavalier with Idle Problems

Tiny
MINERVA122
  • MEMBER
  • 1991 CHEVROLET CAVALIER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
My cavalier has issues with idling extremely high and pouring fuel from the injector in the throttle body. It will shut down at low idles and you cannot get the RPMs too low on the interstate or it shuts down. It seems like the RPMS jump then fall quickly. It surges in power then bottoms out. Mostly it will hold that extremely high idle after starting for minutes and minutes. The car has about 177000 miles. It will crank over and over when starting like the timing is off on the older vehicles, but the computerized cavalier doesn't have any way to adjust it does it? I've tried every sensor I can think of and I don't know what to do. Suggestions please?
Friday, December 28th, 2007 AT 9:23 AM

5 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Lets get that fuel pressure checked out then investigate what's happening with idle air control valve-could be a dirty air bypassages or the valve itself and also the throttle position sensor resistances/voltages.
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Friday, December 28th, 2007 AT 12:08 PM
Tiny
MINERVA122
  • MEMBER
  • 3 POSTS
The IAC Valve, EGR, and PCV valves are new, as well as a new crankshaft position sensor. All the fuel and throttle body parts have iether been checked or changed, and the IAC is not sticking. It blows the heater/AC fuse as soon as you turn the key on with all these accesories unplugged and we bypassed that section of wiring form the Electric fan thermostat sending unit all the way to a switch in the dash and the same with the electric fan. It has new coil packs and the plugs are all firing.
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Friday, December 28th, 2007 AT 12:14 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Disconnect the positive cable put a test light in between the disconnected cable and battery pos. Post is the light On? If so start removing fuses and unplugging connectors the one that shuts off the test light is the trouble circuit.
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Friday, December 28th, 2007 AT 2:17 PM
Tiny
MINERVA122
  • MEMBER
  • 3 POSTS
Could I try a new Map Sensor?
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Friday, December 28th, 2007 AT 2:29 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
You're throwing money to it find the short circuit maybe that's the one that's causing the problem
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Friday, December 28th, 2007 AT 3:46 PM

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