A few idle issues, and running problems

[89Joe]

I need some help on this one. First off I have an 89 n/a auto, with a new tranny,and motor. Recently the car has began to idle very rough, It stays around the factory idle settings but dips down to about 500-650ish and back up as if someone was revving it to and from. I realize that my TPS isn't properly set (code 41) so I contribute the issue toward that.

The improperly set idle hardly impairs the ability to drive the car, yet, is bothersome enough to be concerned, for it seems to effect other things. I notice that I get noise from the rear end of the vehicle, but think its the fuel being sloshed around in rhythm with the idle. However, it does sound as if something is banging around back there. All this occurs during park, and very rarely during drive. On occasion it does stall but not often.

This evening I became very concerned, while driving home the car for some reason seemed to trip, almost stalling, this occurred very briefly. The check-engine light came on for a moment, but went away as if the car caught itself, and after ran great as if nothing happened. I have no further information regarding this, and I couldn't pull any codes because it was too dark out.

I would be very grateful if anyone could contribute to helping me solve these issues, for the problems are beyond my current knowledge.

-Joe

 

[mickyg]

Just as a guess, sounds like a vacuum leak. The "hunting" you're describing could be the IAC trying to compensate. Any leaks I've ever noticed tend to not be a problem when the throttle is open (ie, not idle).

Could be worth using the old "hose stuck in your ear" trick to see if you can find any hissing around the intake hoses and vacuum lines.

As for your sounds coming from the back of the car - not much help here, I'm afraid.

 

[89Joe]

Micky you were right! I did have a vaccum leak! Sorry I haven't said anything in reply to your post, I was a bit busy this week. Turns out my ISC's bolt was loose. I tightened it up, and now the car runs freakin amazing! So damn smooth, you could swear it was new! As far as the noise in the back, I think I was just being stupid on that one...was just fuel sloshing around:icon_bigg.

-Joe

 

[Jspec7m88]

Hah...As soon as I read your first post about the idle dropping, I was getting ready to scroll down and type one thing. ISC.

Looks like you found it!

 

[89Joe]

Yea, I was just being stupid on this one. I was thinking to big when it was just a minor thing:nono: .

 

[mickyg]

Glad you got it sorted out! Where abouts in MO are you? I used to live in Joplin.

 

[89Joe]

I live in St.Peters, and its starting to become quite developed, and crowded. Not sure where Joplin is...have to go look it up, but thats cool. Too bad you don't live here anymore, could've gone for a cruise or something:biglaugh:

 

[mickyg]

Joplin is near the Arkansas, Oklahoma, Kansas border. Yeah, cruise would have been fun!

 

[supramacist]

I am originally from fayetteville arkansas. I lived in tulsa oklahoma and st. louis mo. edwardsville illinois, long beach, ca. san diego, ca. ft. smith arkansas, and hopkinsville kentucky

 

[thunderz]

Hah...As soon as I read your first post about the idle dropping, I was getting ready to scroll down and type one thing. ISC.

Looks like you found it!

What is the ISC?

 

[thunderz]

What is the ISC?

OK I know what it is...my problem starts when the car gets to full running temp and its like a switch was flipped and the idle gets rough and I get little back fires etc. Does anyone know what this might be?

 

[89Joe]

OK I know what it is...my problem starts when the car gets to full running temp and its like a switch was flipped and the idle gets rough and I get little back fires etc. Does anyone know what this might be?

Check for codes, and could you be more descriptive about the idle issue. It's possible the problem could be replated to worn plugs and wires. Before anything else however, check for codes.