Hey guys I have a 2000 Chevrolet Camaro 3.8l, i've owner her for around 7 years now, she got me to point a to point b for over 80,000 miles. Recently however she has been sitting for 4 years, however I have been starting the car and driving it around for those 4 years. But for the past year and a half i keep having a stalling issue at idle that I cant seem to solve. It will stall at stop lights and stop signs. It will also stall when it idles in a parking spot for too long. I am not sure what to do at this point seeing how I have replaced the; Alternator, Plug wires, Plugs, Fuel pump, fuel injectors, fuel pressure regulator, fuel filter, air filter, MAF sensor, MAP sensor, and PVC valve. I have checked the fuel pressure and it is within specs, I have checked the fuel pump relay and fuses and they are all good, I have put seafoam fuel treatment in and added 93 octane fresh new gas to the tank and nothing has worked. Also no engine codes are showing up. If anyone has any ideas or information that can help I would be forever thankful, I just want to get her back up and running after sitting so long.

 

plugged cat maybe. does the exhaust sound like it has a hiss to it or seems more quite than normal?

 

Stalling with no Codes? Try shaking the wire harness for your sensors, injectors and ignition system. MAF pigtail is suspect since it out in the heat and sees a lot of vibration. You could also try cleaning and rehoming the IAC and testing and cleaning the EGR Valve. (see YouTube). Some times dirt will not let the IAC react fast enough to keep the car running. The EGR valve needs to seal at idle to stop exhaust from getting into the intake. They should never open at idle. Sometimes dirt hold them open a little. This screws up the fuel mixture. O2 sensors? if they are reporting wrong it can screw things up. They should be done every 100K or so. I have had a few times that I have replaced O2's and then the engine set a code. There was nothing wrong with the new O2 but now working O2 is seeing an issue the old one did not. How is the coolant level?

If a cylinder stops firing you normally get a Random Misfire code. That the code the PCM throws when it sees a cylinder not firing regardless of the reason just based on RPMs. If all the cylinder died at the same time it may not set a RM code. I would expect a lean code if it was running out of fuel and a Rich code if the spark was not firing the fuel with the time it takes to stall.

To do it right with no codes you will need to find someone that has a scope. A scope will tell a trained person what is happening in the cylinder. Weak or no spark, Lean or rich even compression and timing issues can be read in the spark fire pattern on the Oscilloscope.

 

To my knowledge my car does not have an IAC, it is drive by wire. Also I removed the EGR valve and had it deleted from the PCM. I doubt this could be causing the issue seeing how it still stalled before I did the EGR delete. I am going to replace all o2 sensors to make sure none of them have carbon build up, but electrically they are sending signals to the PCM, they just may be faulty readings due to clogged. Not sure if anyone around me has an oscilloscope but I can look into it. I'm close to giving up and scrapping the car because i've been working on problem for over a year and i've taken the car to 3 mechanics and none of them are willing to help me. They either lie and say it doesnt stall or outright tell me they dont want to bother with it, too much work. Also i replaced exhaust manifolds with pacesetter headers and built a custom exhaust all the way to rear axle, no cat anymore. But still has all o2 sensors.

 

No check engine lite? Removing the EGR valve and the Cat should set the check engine light. It may even put it in limp home mode. Can you adjust the base idle on the DBW? Sorry My 3800 was a 96. Some cars have a base idle that can be adjusted.Other can be adjusted with shims. Small vacuum leaks could cause idle issue. Way back in the late 80's and I did driveablitliy warranty repair for GM, low idle issue issues where the hardest to find. Even the most minor thing car cause idle issues at low RPMs. I would try to avoid idle issues in the TPI camaro/corvettes cause they always ended up straight time. No flat rate. No way to make real money.

Do not worry about the the after Cat O2s all they do is monitor how well the cat is working. Most higher end Snap on scanners have built in Scopes. You could also try to read the plugs right after it stalls. Pull the vacuum off the regulator and increase the fuel pressure.

Want a hobby? Learning how to read a scope can be time consuming but with the internet who knows.

 

Yeah no check engine light from EGR or Cat delete. I had a shop delete it when they flashed the PCM for me. They didn't mess with the base idle much from what I heard. I didnt know pulling the vacuum hose from pressure regulator would increase the fuel pressure. I can look into getting a high end snap on scanner but dear god its probably worth more than my car at this point. Yes, I am well aware that they wont be making real money off me and that low idle issues are a pain in the ***. But at the end of the day someone needs to fix it or its just a giant paper weight.

 

I have never seen any cheap snap on scanners. I would have one. At the dealer I used a Sun or a Bear Scope back in the day. I have an older hantek from Amazon with a plug pickup now. Seems like it works ok. I think it was $70 There is a lot of a good scanner can see a scope can't. Like recorded Missfire.counts. Is it in close loop. When the RPMs drop does the throttle try to comp?

 

Yeah I have a bluedriver scanner but it cant do anything fancy. I am in the process of getting a better one, its the XTOOL D7, supposedly pretty good. Yes with the scanner i have now the throttle does try to compensate, it opens up even more to around 27-30%, the RPM's just slowly go from 1700 to 1300 then it dies. It only happens when it is fully warmed up. I have checked the vacuum hoses and fittings but they all feel nice and snug, no holes, cracks or hardness

Update: I replaced the o2 sensors and the fuel trims got better. I got a better scanner and can see if the engine misfires now, and it is misfiring on all different cylinders, mostly cylinder 2. But they are sporadic and intermittent, which i'm assuming is why they are not causing a code to come up. Next i will tackle coil packs, but i have my doubts. I'm guessing that it might be piston rings, valve springs, or wiring harness has been chewed somewhere. This is a very confusing and frustrating problem to isolate.

Update 2: I replaced spark plugs, wires, coils and tested engine it still stalled when engine got hot. I also did a smoke test of the intake to see if there were any vacuum leaks, it checked out there were no leaks. Then I took the throttle body off and cleaned it out of all carbon to make sure the valve was not sticking, but car still stalled. Now i am going after crankshaft position sensor but I cannot find a replacement harmonic balancer bolt. Wondering if the Buick, Pontiac and Monte Carlo L36 bolt could be interchangeable?