Symptoms of bad head gasket
 

My car has been running pretty good minus a slight hesitation with opening the secondaries when not fully warmed up. Once fully warmed up they seem to open up normally after I have gone WOT a few times. Its like they are almost sticking, but I heard lazy O2's can cause this. Will be replacing after my header swap.

Now to the serious issue. Lately if I drive my car for say 30 minute or more then go to shut off the engine and re start it a few minutes later it runs really rough. Almost as if one of the cylinders is misfiring/not firing at all. If I rev it up a bit, and start to drive the engine seems to run fine within a few seconds.

I remember my old 96 Neon when its headgasket went out behaved similarly except when it would run rough, it would continue to run rough until it completely cooled off. The ZR-1 isn't exactly doing that.

What are some of the symptoms of a bad head gasket?

Re: Symptoms of bad head gasket
 

That's a symptom most usually associated with a leaking fuel injector

Re: Symptoms of bad head gasket
 

I replaced all the fuel injectors almost 2 years ago. They are the accell brand. At the time of replacing the injectors I also changed the fuel filter.

Re: Symptoms of bad head gasket
 

Find someone with a scanner that has diagnostic capability. They will be able to check the 02s and lots of other things before you start throwing parts at it.

Re: Symptoms of bad head gasket
 

I have a MT2500 available in my toolbox.

Re: Symptoms of bad head gasket
 

Check the cross counts of the 02s. I had one that was very slow and caused a small hesitation.

Re: Symptoms of bad head gasket
 

Actually, the right way to diagnose a potential leaking injector is to run the fuel pressure tests in the Service Manual. For that you need, obviously, the FSM for your model year and a pressure gauge appropriate for checking fuel pressure on a GM port injected engine. The gauges can be had from a number of vendors.

Re: Symptoms of bad head gasket
 

Was just referring to checking the o2s

Re: Symptoms of bad head gasket
 

In my experiences with blown head gaskets is that you will see a ton of white smoke coming out the exhaust, as all of the fluids are now mixing together. You may or may not notice a significant change in performance under normal driving conditions. I have not experienced this in any car that I have owned, but have had this happened in some of the big trucks that I have driven over the years.

Re: Symptoms of bad head gasket
 

Today was probably the worst it has been. I drove the car from work to the gym, roughly 30 minutes driving time. Vette ran great. Pulled well on the highway nothing a miss. The car sat for about 30-35 minutes outside. When I went to start it up, the idle was very rough and pulsing up and down, like it was hunting to find the idle. I didn't touch the gas pedal and let it stablize by itself. It took a 30 seconds before it idled at 1000 RPM's.

I haven't changed the plugs or anything yet. When I hook up the scanner what should I all be looking at?