I have a 91 Loyale wagon that the check engine light comes on every now and then. When the light comes on, the idle constantally canges, going from 800 rpm up to about 1500-2000 rpm and back down rappidly. Any ideas?

Thanks

You should check the ECU for trouble codes. Read here to find out how http://www.usmb.net/repair/?CurrentDirectory=FOLDER_3f29b58f4430b8.49200047/&FileType=Article&File=ARTICLE_3f2c055f4862e9.39782181.art

 

My best SWAG would be a bad purge contol solenoid.

i will bet it pulls a crank angle sensor code, causing the surging idle. this was the problem on the 4x4 conversion sedan we had

I have a 91 Loyale wagon that the check engine light comes on every now and then. When the light comes on, the idle constantally canges, going from 800 rpm up to about 1500-2000 rpm and back down rappidly. Any ideas?

Thanks

 

yes my 94 loyale did that the check engine light came on, it was a code for a idle air speed control valve, the car would start racing up and down then the check engine light came on, see if this is the same instance or code, this only did this now when i came to a stop at a light or just at idle

yes my 94 loyale did that the check engine light came on, it was a code for a idle air speed control valve, the car would start racing up and down then the check engine light came on, see if this is the same instance or code, this only did this now when i came to a stop at a light or just at idle

It doesn't happen all the time, about once or twice a month but its starting to happen more often now

Sir Mudduck, Mr. Chadwick is pointing you in the correct direction I believe.

 

The IAC or Idle Air Control on these SPFI cars is prone to "gumming up" to use

a lame statement. They need periodic cleaning. This is such a common problem

I would almost list it as a maintenance item.

 

This unit mounted on the front of the throttle body.

A canister shaped devise with a rubber line and a

electrical pigtail.

 

IT can be removed (four screws - one or two can be buggers) and the gum cleaned with any fuel injection spray cleaner,

some people have had success by removing the air line to it and spraying the cleaner into the body of the IAC.

 

 

It would be advised for you to find the time to check for stored error codes,

( BTW I revised the USRM article to make it more explicit after reading the link Craig provided).

 

The error codes may tell you the EGR solenoid is bad or,

as Craig mentioned, the purge control solenoid.

 

However there is a chance the electrical connection to the IAC is wanting cleaned or repaired.

Or the IAC has an intermitant open in it's windings.

 

This in turn will also illuminate the CEL.

 

Good luck on how ever you choose to attack this problem.

Sir Mudduck, Mr. Chadwick is pointing you in the correct direction I believe.

 

The IAC or Idle Air Control on these SPFI cars is prone to "gumming up" to use

a lame statement. They need periodic cleaning. This is such a common problem

I would almost list it as a maintenance item.

 

This unit mounted on the front of the throttle body.

A canister shaped devise with a rubber line and a

electrical pigtail.

 

IT can be removed (four screws - one or two can be buggers) and the gum cleaned with any fuel injection spray cleaner,

some people have had success by removing the air line to it and spraying the cleaner into the body of the IAC.

 

 

It would be advised for you to find the time to check for stored error codes,

( BTW I revised the USRM article to make it more explicit after reading the link Craig provided).

 

The error codes may tell you the EGR solenoid is bad or,

as Craig mentioned, the purge control solenoid.

 

However there is a chance the electrical connection to the IAC is wanting cleaned or repaired.

Or the IAC has an intermitant open in it's windings.

 

This in turn will also illuminate the CEL.

 

Good luck on how ever you choose to attack this problem.

Cool. A friend of mine also suggsested cleaning out the thottle body also. Going outside to do that as soon as i get done typing this. I will let you know the results. Maybe I will have a smoother idle also sience it idles a little rough. Thanks again.

I am having the same proplem except my battery is also going out aswell any suggestions.

Ok i oulled the air intake off the throttle body and remaved the top part pf the throttle body and sprayed the hell out of the throttle body with cleaner. I guess i will have to see if the light comes back on or not. it sure does idle smoother and responds a little better thougf. There sure was alot of gunk and goo and crap built up in there.