yes I noticed the other current thread about the same topic but that is about autos.

Anyways, last Friday I had to change my blown heater core and when it was done I hooked back up the neg. terminal started the car which didn't work the first time as usually but then not the 2nd, 3rd or 4th. It did start the 5th time but was looping very bad. It settled down a bit so I took it out for a drive and once the engine was warm the rpm's proceeded to nose dive every time I came to a stop, stopping just shy of stalling. I wasn't worried cause my old 92z used to do it all the time then just go away. Now 3 three days later the car will stall every time I come to a full stop unless I can catch it before it does, which is becoming harder and harder to do. If I can stop it, it will still idle like crap and when it does stall it will take 2 or 3 tries to get it to start again.

I don't see what I could have really messed up changing the heater core cause I didn't really touch anything unless it is an electrical problem from having my battery unplugged or something getting wet from draining coolant or from the core leak. The car has only 120 000 km on it and was perfectly fine before the core blew aside from needing an oil change.

Needless to say this problem is most embarrassing consider I have to drive through 2 different cities downtowns to get to work and I'm sure its not good for the car. Any help would be appreciated to help me fix it myself before I suck it up and take it to the dealer on Wednesday.

Thanks

Idle relearn, perhaps? I mean, you DID say the negative battery cable was disconnected. Sooooo...it seems like you just need to let the 'puter do its thing with some driving. Clean your TB also. Probably has nothing to do with it, but it can't hurt.


-----------------------
1997 Cavalier Z24
1992 Cavalier Z24 - *RIP*
"I consistently feel like something's missing out of the new cavvy. I'm pretty sure its 2 cylinders."

sounds like a vacuum leak, check around the area you worked on the heater core.

idle relearn...i just went through this...exact same symptoms....did the idle relearn yesterday and it fixed it.

Idle Relearn

I did the idle relearn as per v6z24.com and it appears to have done the trick. The idle is still a bit to low for my liking so hopefully it will get better after a few days or driving. Its wierd cause I have had j-bodys for the last 8 years and this is the first time I have had to do a relearn.

thanks for the help.

Bumping this topic up...

I'm having these exact symptoms in my '93 Z24 5spd--RPMs slowly decreasing at idle, sputtering, and stalling if I don't give it gas before it dips below 500rpm. I recently had to replace the (dead) battery so I did an idel relearn as instructed on v6z24.com. Actually, I think the problems might have started happening AFTER that, but my mind is a little foggy on that.

Anyway, I have tried replacing the fuel filter and PCV valve, cleaning the throtlle body, changing the oil, and filling up with "better gas" in case I got a bad tank from the discount station. The fual pump is still original *knock on wood* but I had to have the rusted-out gas tank replaced and the mechanic who looked at it said the fuel pump/sending unit was OK, so he didn't replace it.

I just did another idle relearn and it's running OK, but still dipping RPMs at idle a little bit. What else could be causing this problem? Plugs/wires? Timing chain?

I'd look at a few different things. The Tee right where the fuel pressure regulator is can easily come undone and will tear if inserted too far. incorrect fuel pressure = bad...

If you replaced your PCV valve, i'd be concerned with a hairline crack in the pcv hose -- there were two styles of these lines, one was a curved, rubber piece, and the other was a two part rubber/plastic unit. with sharp 90 degree bends. The curvy rubber hose is known to fracture and tear while changing the PCV valve, opening up a nice sized vaccum leak under the intake plenum. since the PCV is primarally partially occluded during idle, it may not be realized, but at higher engine speed, the change of vaccum pressure (pushing clutch) may create enough of a pressure differential to confuse the MAP sensor and run you rich, causing your idle to drop. (also, your FPR will react similar).

Obviously your IAC works, because it wouldn't idle or go into 'high idle' when the car starts, or you turn the steering wheel hard, fan turns on, a/c turns on, etc... that would cause different issues.

Let me know what you make of this. you will have to pull the upper intake plenum, gaskets are cheap at autozone, you *can* get away with leaving the TB attached and just lifting up the alternator-side of the plenum to check it. New hoses are available from your local GM dealer for around $10 if i remember right.

--Lee



-=[2004 JBody Bash - '82-'94 Street Modified - Third Place]=-
http://www.turbochargedsoul.com/

[TZ3] 1994 Cavalier Z24 Convertible, Automatic, (Boost around the bend)
[TZ2] 1993 3.1 Liter V6 Intercooled TurboChevrolet Cavalier Z24 Convertible 5 speed
:: REST IN PIECES :: (Parts available, PM me!)
1994 Subaru Legacy L AWD Wagon 5sp/EJ22 - Daily Driver
N3LEE - Amateur Radio

i have the same problem as fermi with my 90 Z24 5 spd....i ended up cracking my UIM and EGR plate and i couild only get a newer style plenum with the bolts that have the rubber surround on them....and now my car always stalls when i push the clutch in under a load,ive sprayed carb cleaner everywehre and i cant find a change in idle at all...i also changed my IAC and MAP sensor with the ones from my 3400 sittin in my garage but that did nothing i might trying running a hose around the plenum wiht hte other end at my ear hoping i can hear a leak somehwere



FDP 62MM TB, FFP Performance Chip, FFP Underdrive Pully, WAI, Hi Flow Cat, 2.5" Catback, Functional Ram Air Hood, Centerforce Dual Friction Clutch