Greetings all! Of course my first post pertains to a problem =P

Car Details:
1990 IROC Z28 Camaro
305, TPI
All stock except exhaust and high-flow catalytic


I noticed the problem about a year ago. Whenever the car idles, I noticed what seemed like a loping or surge. It felt like the RPMS would just drop, stutter for a slight second, RPMS would jump, and then it would level out again. About 5 months later, after driving approximately 70 miles, I came to a stoplight and it just died on the spot. I was able to crank it up and get home. As time progressed the loping or surging got worse, and if it cut off, I was unable to get it started up again until after letting it cool down. It never idles over 225-230. I began noticing clear smoke out the tail pipes after initial start, and noticed gradual decrease in coolant levels. Are all these symptoms of a head gasket?



Most recent work:
1-2 years ago:
--Replaced lower intake manifold due to crack
--Water pump, hoses

 

Sounds to me like a vac leak thats getting worse. Check all your vac lines visually for cracks and if I remember correctly some of the lines have plastic sections that tend to break commonly. If you dont see anything or hear any vac leaks with the engine running you could take some carb cleaner and lightly spray around the intake manifold and listen for the engine idle to increase. Could be your intake gaskets too. I would suggest doing this when the engine is somewhat cooler, but you can do it when its warm too just be careful so you dont end up with a fireball under the hood. The proper way would be to check it with propane or smoke. Head gaskets tend to blow a white colored smoke from the exhaust and misfire after the engine is started cold. You could pull the plugs and check if any of them look different from the others. A breached cylinder will have clean looking plugs. Also fill you radiator to the top and look for air bubbles when the engine is running. Or take it to a shop and have them do a leak down test on it. You might also be able to find a block tester at a local parts store to check for CO2 gasses in the cooling system key indicator of a blown head gasket or cracked head

 

Although you may have a leak i wouldnt be too concerned about a head gasket just yet. Thats usually associated with other symptoms like white smoke and over heating oil contamination stuff like that which u havnt mentioned anyways. Surging idles are usually the result of a failure of the EGR valve. I would deffinetly locate the leak but i would also at least inspect and clean out your old EGR valve.