Need some help. I am getting the current SES codes: 15, 33, 36, 42, 43. I replaced the coolant temp sensor and coolant temp sender and the car ran good for about 20 minutes without any codes. Now all the codes are back and the car is running poorly. Any suggestions on where to start? Thanks, Tony

 

With that mix, I would almost think you have a harness or grounding issue. 36 is really unrelated to the rest unless your MAF has a plug issue.

So, let's start with some information on your car. Year, Engine, Miles, Mods, etc.

 

Kyle! thanks for the reply! I am new to this group.
I have a 86 iroc camaro with the 305 tpi, 106,000 miles, no modifications. The car runs very poorly and is dying at stop lights. I am still able to drive it, but its not performing like it should.
You are the second person to mention grounding issues. I just checked the ground on the back of the cylinder head. Not really sure what I am checking, but it looks connected at the firewall and cylinder head. The ground at the cylinder head looks a little corroded, but Its very difficult to see.

 

That helps, you are dealing with a MAF car, so as I said ignore Code 36 for now. It has no impact on driveability. I was hoping a mod would move this to the TPI section.

When my cars had similar problems in the past, it has been issues with the MAF. MAFs are very hard to test but you can do a few things. One is unplug it. If it runs better, its probably your culprit. Another is to tap on it as it runs and see if it gets better or worse. Either way, it still says your MAF or its connection have issues.

So how healthy is the car? Good fluids? Good Gas? New Filters? How are the plugs/cap/rotor? Have you cleaned the IAC and IAC passage? What is your fuel pressure? How long after you turn the key off can it hold pressure? You could also get some MAF cleaner and clean the inside of the MAF.
With all of that, I would also suggest after cleaning the IAC housing and the IAC that you perform the minimum idle procedure (You can search it on here).
After confirming the health of all components, I would then disconnect the battery to reset your codes and see where you are with it's running condition and what codes return.

 

Plugs/cap/ rotor recently replaced. It has been sitting for 3 years. I have run through 2 tanks of gas so far this summer.
Current issues: check engine light comes on while driving. Car comes to a stop and then dies. Restart car no service engine light. Drive for a few minutes service engine light comes back on. Recently noticed that the temp gauge is reading very low below 100 while driving.
I did tap on the mass air flow sensor for about 1 minute then I drove the car and it drove very well for about 15 minutes before the SES light came back on and the car died at idle. Thanks for your help this is frustrating.
Im leaning towards replacing the IAC, TPS sensor, and lastly MAF sensor (because of price). Im hoping replacing these parts will fix the issue.

 

Unplug the MAF

Don't just replace parts, get the issue isolated. It sounds like you have a MAF or MAF plug issue. The car should run just fine with the MAF unplugged, take it easy, but should do just fine if the MAF is the issue. This is not a definitive test, but a MAF is very hard to test. Unless you have a data logger and can see the readings the ECM is receiving (And you should get some method of doing this if you are keeping the car), unplugging is about the best you can do.

The TPS can be checked with a volt meter. Probe and read the voltages before replacing.

IAC you should make sure you clean the housing, the pentil and do a reset before you replace

 

The best way to test all your grounds is to take your multi meter get a good reading of volts off your battery. Now take a reading off your grounds it should be pretty similar if not you got an issue with that ground. Like stated above check your TPS voltage super easy takes like 5 mins. Also clean your IAC valve n set it to spec.