I just inherited have a '86 Camaro 2.8L\Auto. I gave it a complete tune up, fuel&air filters. Car starts right, goes to high idle, runs great for about 5-10 mins, then it it seems to go flat, must be in limp home mode. I have no SES light, but the lite is good. I can trip it to test it. I checked for stored codes, it's clean. Must be a sensor. Any clues on where to start...maybe coolant temp?

 

I got a gut feeling it's the O2 Sensor. I'll start there...it's cheap & should be replaced anyway.

 

MV,

If the ECM is in Backup Fuel (Limp home) mode, there should be a MIL lamp on the dash. If the O² sensor isn't functioning at all, there will also be MIL lamp and DTC stored in the ECM. Your lack of trouble codes doesn't support the idea of a completely failed sensor, but you may have a sensor that is almost out of range but not far enough to set a DTC.

If your O² sensor is more than 30,000 miles old, it's a good idea to replace it anyway, but that may not solve the problem.

It's easier, faster, and certainly cheaper to do a little diagnosis of the sensors before replacing them. For the cost of a new O² sensor you can get a cheap digital multimeter, and start homing in on the real problem. Most of the sensors can be tested effectively with a DMM.

If you do get a new O² sensor, also pick up a small jar/bottle of anti-seize. They never supply enough with the new sensor, and you'll be using it later anyway.