95 z34 idles up and down (sometimes dies)

[lildragnjoe]

On cold starts my baby idles up to 3k the back down to 1k (if it doesn't die) on cold starts...The shops round here can't figure it out cuz the check engine light isn't on they say.. Any ideas?? I've run fuel enjector cleaner thu it, changed the plugs and all that. Nuttin helps..I'm lost!!

[AFAN4-29]

When it does rev up to 3k at any point is the engine running rough? Does it ever hapen to you on a warm start, or just the first cold start of the day? Almost sounds like the Idle Air Controler is not functioning properly. Is this something that has gotten worse, or just started to happen. If you keep your foot on the gas will it stay running? Any more info you may have about it, let me know.

[lildragnjoe]

This has been goin' on for a few months now. It all happened one morning out of the blue. No warning signs the night before. When I first crank it up, it heads straight to 3 - 3.5k, then back to 1 - 1.5k (spits and sputters there for 5 sec) then back up. (if it don't die) At the higher rpm, it runs smooth. Givin' it gas will keep it runnin with an occasional miss. After that battle, I drive 15 miles to work. The drive helps for the idleing problem but she's lackin on the open road. Seems like my hp got left back at home on the front porch. The problem isn't gettin any worse. But.... you know...it still bites. Someone mentioned today that there was not much flow commin outta my exhaust. Could a plugged catalytic converter do this?

[AFAN4-29]

Here is what I found, doing some poking around the net. I have heard of this happening, but didn't know the symptoms. My buddy works at a GM garage I will run this past him, and see what he thinks. But from what I heard if you have the intake leak, you will have pos antifreze loss and oil loss. I have a 2001 LS and my buddy had to fix a couple of them with bad gaskets, but they just leaked coolant.

I have a 97 monte carlo z34 with 103,000 miles. The problem you are all experiencing is the upper and lower intake manifild gaskets. The reason that the car revs high and low repeatedly is becasue of a vacuum leak. The enginge is trying to compensate for the lost vacuum by sucing in more air.

To anyone with a bad idle on the 3.4. What you're describing is bad intake gaskets. The upper and/or lower gaskets tend to break and leak if not put in very carefully. This is a very common problem. What happens is that the car idles very poorly when cold, but once warmed up, the problkem is mysteriously gone.

I know when my Cat was plugged in my 94 Lumina, it was hard to start, and when you pressed the gas, it sounded like the rev limiter kicked in. But would idle fine. I hope this helps, I will keep checking around for you.

[lildragnjoe]

Thanks a bunch for all the info and speedy responses!! But my wife disagrees, she says that's not it cuz it'll cost too much to fix.. Now all I gotta do is find a decent shop in the area to tear into it and see. Cuz Im not pissin with all that stuff. Whatever happened to a carborated V8?? THANKS AGAIN.

[whiskybent24]

I had the same problem with my 95/Z34.The problem was a intake leak,and after it was fixed I no longer had the problem.The car now runs fine.

[GrZo]

Hi, I am having the exact same problem with my 95 z34. What's wierd is that my temp guage never gets above 110 degrees. I thought that was the problem, originally, but after looking around, and adding a post at the mymonte.com website, I got responses with similar answers. And what sucks is that the car has 35,000 miles on it. I'm booked at my repair guy, who fixes what I don't want to, for next week or so. He estimated $150 to $175.00 for parts and labor. I am going to have him throw a new Coolant sensor in right away, since it's in the same area.

[Jerrymonte]

it seems that i to may have the same problem. i have a 97 z34 mc. out of the blue i go to start the car and the idle goes up, then down, then up, then down, then dies. i have checked the fuse box on the front passenger side, and added fuel inj cleaner, but still no dice. right before i filled up my gas tank, then it sat @ 10 min. could it be the fuel filter? a mech said that most of the car still had its original parts, so i dont know. PLEASE HELP!!

[fist]

Before you pay the price to fix it try to start it and listen for the sound of hissing air in the bay! Follow it and you will find your leak! If you don;t hear it follow the vac line this is very easy cause only one goes behind the break booster

Also check your PCV dipstick and oil filler cap! If you have a milkshake like substance on any drain your oil! re4place it and keep an eye on the coolant! If this occurs then you have a lower intake gasket leak! I would repair this yourself! Get a chiltons and Victor gasket set normally from napa to replace the ones blown!

[montie0690]

MAF sensor fixed my idel problem about 40.00 at advanced

[NSPUSMC]

I have been having the exact same problems with the idle. Great on the highway though right guys? After talking to a mechanic and doing some research, I sort of just decided that it is in fact an intake leak. So, I went ahead and got a backdoor mechanic to start tearing into it. I havn't gotten it back yet and he still hasnt told me if that is the problem for sure. I sure hope it is cause I am paying him a pretty penny. I will let you all know how it goes.

After the months of having this manifold gasket blown, should I replace the fuel filter? I dont know a damn thing about cars.

Also, I am wondering how much I could get an l67 3800 engine for? Any ideas? I would like to ditch my 3.4 after I get it fixed.

[Ethan504]

my dad has a 96 Monte Carlo and it did the same thing, it kept dying and revinng up real hard when he was in park and then goin real low
it was the o2 sensor, had it replaced and has never done this since

[stock03GT(fornow)]

Are these intake gaskets a do-it-yourselfer for a guy that is moderately versed in mechanics??

[ulies8]

I have the same problem i changed the ecm computer cam shaft sensor tune up air idling valve upper plinum gasket and i still have the same problem please help.

[ulies8]

Originally Posted by ulies8

I have the same problem i changed the ecm computer cam shaft sensor tune up air idling valve upper plinum gasket and i still have the same problem please help.