my 1988 iroc-z 305 tpi was running rough and i noticed the exhaust was rich as it smelt strong... it runs good for about 10 or so minutes and then it bogs out like it is flooding. that car gave me code 33 and 34, but i tested and it is not the mass air flow sensor that is causing the rough idle and stalling, i also noticed my engine coolant temp gauge was reading -38 degrees celsius, but i didnt get a code for a faulty coolant temp sensor..any help would be great

 

Sounds like a vacuum leak. It's not as obvious until it's off the cold startup enrichment. Once it stops being rich on warm up, then it gets worse. It could be small but if it's in a critical place it can cause your symptoms very easy and it's very common.

Try spraying starting fluid all around the intake gaskets and see if the idle increases at all.

33 - MAP (Manifold Air Pressure) sensor voltage low - pressure low/vacuum high OR MAF (Mass Air Flow) sensor signal low - flow high.
34 - MAP (Manifold Air Pressure) sensor voltage high - pressure high/vacuum low OR MAF (Mass Air Flow) signal high - flow low.

You are getting both codes? How did you test the MAF to verify it's signal is outputting within the proper parameters? There are a couple ways. Also, have you reset your ECM to clear all the codes and then checked it again after it throws a code?

The fact you mention it bogs seems more like a genuine MAF issue than a vacuum leak. Have you verified fuel pressure at the rail with a gauge by chance? Perhaps your filter is full and it's noticeable under higher flow off idle.

Just spit balling since it could be a few things...

 

There's your problem, right there.

Not the MAF.

Not vacuum leaks.

And don't get me started on "timing" and "EGR".

Fix the things you ALREADY KNOW are wrong with it. Kinda DUMB to try to troubleshoot AROUND something that fundamentally CRITICAL that's OBVIOUSLY messed up, and which BY ITSELF fits the logical criterion contained in my signature.

Be aware though, the solution might not be "replace the sensor"; might be a wiring problem such as a broken connector. Might even be that it's just unplugged.

 

My scanner read low coolant temp too. Ended up I was setting up the scanner wrong. I have since figured it out.

Just for the heck of it.....clean and tighten the grounds on the back of the heads. The one on my drivers side was finger tight! I'd imagine they loosen up over the years from the expansion and contraction cycles.