car races and stalls on cold start

[rossg]

I have a 94 cutlass with the 3.4 I recently had the fuel pressure regulator replaced because the car was hard to start. Now when I start it first time of the day it races up to 3000rpm then the idle drops down and stalls. If I start it a few times and catch it by manualy pressing the gas I can keep the car running If I let off the gas the car surges and sometimes stalls. When the car warms up it is fine I can drive it all day without a hicup. I did get an 02 sensor code but that happens when the car is surging and I don't think that would make this happen. It also when warm will sometimes idle a little high 1200rpm. Any Ideas anyone? Do I need to get my car to re learn its idle?

 

 

 

I am trying to use search on the forum but it doesnt seem to work as I am sure someone else had this problem.

[95 vert]

Sounds like a vacuum leak. Upper intake get sealed after FPR replacement?

[carkhz316]

My euro would do this at least a couple times a week for a couple years before I finally ripped the plenum off and replaced a few injectors. It would start, rev up and and die. Try again immediately after, and its fine. No other problems, just the occasional start up.

[Andrew]

this really could be a few things. intake gaskets, leaky or bad injectors, vac leak, IAC valve.

 

also, i see you replaced the FPR. re-test the pressure at the rail.

[Canada]

Sounds like it *could* be a vacuum leak.

[GutlessSupreme]

Ditto to maybe leaky injectors or vacuum leak somewhere. It could be one of the intake gaskets, maybe it seals as it warms up and expands but leaks when cold.

 

It seems like this is usually a tough problem to solve, just because most of the possibilities aren't necessarily cheap to fix so it may take a while to get through them, or that you find the original problem and fix it, but maybe something else got messed up in the process (like maybe an O2 sensor burnt up due to running rich or something).

[95 vert]

Try spraying something not so flammable like silicone spray around the upper and lower intake while idling. Idle changes when a leak is found.

[jmblimo]

I had exactly the same problem with my '94 as far as the cold start. I replaced the IAC valve and it corrected the problem. (That is the valve that controls the idle speed) You can change it out in 5 minutes. (Torx screws)

[GOT2B GM]

I had this issue way back in the day when I first bought my old 93 Z34. PS idle up switch on the drivers side of the rack was sticking, constantly telling the ECM to idle up.

[waddlemasta]

I'm having the same issue right now. As soon as it warms up its fine. I'm just going to deal with it I guess for now. I only spent $400 on the car so I'm not going to spend any more time and money on it.

[waddlemasta]

Problem solved! I took some Blue RTV gasket maker and went around the EGR where I blocked it off and put a little around the plenum while the engine was cold and then went out two hours later and started her up with no more problems. Still have to figure out why my trans is acting up yet now.

[rossg]

here was the problem I found the lower intake gasket needed replaced. if you want to see how I did it look here.

http://www.w-body.com/forum/index.php?topic=71624.0

[rossg]

Try spraying something not so flammable like silicone spray around the upper and lower intake while idling. Idle changes when a leak is found.

actually you want to use carb cleaner or brake cleaner the idle will rev if there is a leek. Silicone is non flamable and does not offer the same result however my leak was very obvios when I finally found it.