Car engine fades off and then back in when engine is warm

The very first thing to do in a case like this is scan it for trouble codes. That will give you some idea of where to start. Even then, don't just start replacing parts. Find out what the code means and what the possibilities might be. For example a sensor might not be working because of a bad ground or a poor electrical connection. Isolate the problem and then start spending money on repairs or parts.

I've taken it to AutoZone before for code scanning. Nothing came up and no check engine light or anything. He said that it might be so subtle that the ECU doesn't register it as an issue "yet".

Are you talking about previous problems or this problem? While it is true that minor problems sometimes have to occur a number of times before a trouble code is recorded I have a hard time believing that something serious enough to make the engine stall is not registering a code.

This problem. I went to the Autozone and nothing came up. I mean, I can get it started up by applying a bit of gas to it when the engine is warmed up, which is when the problem occurs. But, half of the time it will just die right after the starter does its thing.

But, when it does start. It will tug a bit to get itself started after the starter cranks and you can feel it come back to life. I can send you the video through email of how it sounds.

That's sounding a bit like fuel pump. Have you checked the fuel pressure. And these days so much depends on a strong electrical system. Is your battery fully charged, connections tight and all grounds clean and tight? After all that you might need to spend a bit of money at a shop for a professional opinion. Some of these problems are tough to find and you can spend hundreds of unnecessary parts on the advice of well meaning friends and shade tree experts.

I've had a guy with a Buick who had the same problem. He said they reprogrammed the PROM. He did talk about fuel mixture adjustments and looking at the O2 sensors to see if they were getting symptoms of a lean mixture. Last, he said the MAF/MAP sensor could be dirty and disconnecting it and reconnecting it could be the fix. Best bet is to at least get a mechanic with a full scan ability to test the different sensors out.

I agree about seeking professional assistance. Let us know what you find.

So I've done a bit of research and such to help me. I will be taking it into Conrad's sometime to get it checked, but here's my best guess based on research and symptoms. -My car muffler isn't stock -The car exhaust pops when warmed up on revs -The car sometimes has a weird smell after it is turned off after warmed up -We cleaned the MAF sensor, replaced the air filter, and cleaned the throttle body -Spark plugs changed 1 year ago to iridium spark plugs (didn't make a difference) Based on all of this, this leads me to believe: - I have a lean/bad A/F mixture. Too much fuel going into the engine can lead to unburnt fuel getting into the exhaust, which causes it to pop when there's enough unburnt fuel and when it gets warm enough -The engine gets flooded after it is warm from all the excess fuel when it shuts off so it struggles to burn the fuel quick enough to combust -Bad fuel pump -Bad fuel injectors But as I said, I'm going to take it to Conrad's to see if they can see the A/F mixture as a problem or a bad fuel pump or bad injectors.

I forgot to mention that the ECU was never adjusted after I changed to a straight-through muffler, so that could lead to the A/F mixture being off through the less-restrictive muffler.

Sounds like a good plan. Are both O2 sensors still in place after the exhaust mods? Also have you checked that the catalytic converter is not plugged if its still in place? Those are just things that come to mind. I'm sure the shop will address both those questions when they look at it. Let us know what the outcome is.

It was only the muffler changed, everything else is stock. But, I'm sure that could cause an issue since the muffler is less restrictive so it pours a bit too much gas into the engine to try to compensate for the stock muffler instead of the new muffler.