2000 impala 3.8 stopping and missing

by Dwight
(Ohio)

My wife has a 2000 impala 3.8 150,000 miles that is driving me crazy. I have changed everything I can think of but this thing keeps stopping and missing. It has the pass lock security but it does not come on, on the dash board. A mechanic told me if it was the key switch it would come on. I’ve had it to 3 different mechanics. Chevrolet changed the intake manifold 4/29/2010. That wasn’t the problem, it stalled coming home. They said it was the fuel pump I changed it myself for new factory pump the same one that was in it, fuel pressure good the same as the old one. That wasn’t the problem, Ignition module not it, Cam shaft sensor and the crank shaft not it, Plugs & wires not it, MAF sensor not it. I took out the injectors cleaned them as well as I could and replaced the O rings on 12/30/2010 still missing and shutting down. Sometime it won't start for two days, and you go out the next day it starts up and run like new great power for a day or two then it starts all over again. Does anyone have an idea I’d appreciate it. Thanks



Steve Says,

Hi, Dwight. Thanks for using my website.

There are several things that come to mind when I read your car stall question. Some of the things that might be causing your problem are:


1) Fuel Pressure Regulator. Even though your pressure is good when you check it you could have a pressure regulator that is intermittently faulty.


2) EGR Valve. Sometimes the exhaust gas recirculation valve will cause stalling problems, but usually the car will start back up just fine.


3) IAC. The idle air control valve has been known to cause similar problems on Chevy Impalas.
4) Oxygen Sensors. I've heard that faulty o2 sensors can cause car stall problems, but I think this is unlikely.


To help you narrow down the possible causes of your car problem you need to get a fuel pressure gauge that you can tape to your window, then get an inline spark tester that you can hook between your spark plug and spark plug wire that you can see from inside the car. You need to hook them both up then take your car for a drive (or just start it and run the engine) until it stalls. You need to keep your eye on the fuel pressure gauge and the spark tester to see which of them drops out.


This will tell you whether you are losing spark or fuel pressure. Once you know that you can go on testing the components to that system. Feel free to let me know what your test results are and I can help you more. Please let me know what the problem was if you figure it out.