Could possibly be a dirty/faulty mass airflow sensor (located near air intake)

 

Hopefully it's something as simple and easy as that. He's still trying to figure out what might be causing the problem. I don't remember if I mentioned it in my earlier posts but sometimes the idle is erratic. Sometimes it goes low like it wants to stall out then surges to normal then lowers again, like it's hunting for the proper rpm's. Not all the time only sometimes. And it still sets no trouble codes.

 

The symptoms are similar to a faulty mass air flow sensor but, 1995 CMFI doesn't have one.

 

Just got a call from the mechanic. It was a bad temp sensor. It had no codes. I'll ask how he was able to figure it out. That's another $248 on top of the $1567 to get it running! I could've bought a 97 for $2000!
Hopefully it'll run for another few years with no more problems!
Thanks for all the help guys.

 

It's very possible for the ECT to be calibrated improperly and not set a DTC. As long as the ECT is not shorted out or open, and it sends data to the PCM that is within its normal range, no DTC will be set. The ECT sensor is the only data stream that the PCM has for determining coolant temperature. Easy test is when the engine is cold, first thing in the morning before starting the engine, compare ECT and ACT temperatures, they should be within 2 degrees of each other. At normal engine operating temp, the ECT should indicate ~200F.

 

yup it was the temp sensor. He said since we were having such warm weather--for Dec--the temps were somewhat close together, that's why the ecm never set a code. Pretty much what you just described!
You know your stuff buddy!

 

Thanks. Both ECT & ACT/IAT are thermistors. The resistance of the sensors changes with the temperature. On a cold start up, ambient temperature affects both sensors equally, no matter what the temperatrue is, which means they should both read the same. Don't let him pull the wool over your eyes about your warm December temps

 

He does seem to know his stuff. Since I'm new to the area I went by word of mouth about his honesty(mother's). Now pricewise is another matter!
Thanks again Captain Hook! You the man!

 

I had the same problem with my 2000 4x4 blazer and found the transmission fluid to be very low and had a burnt color to it. Also, the cold air sensor had gone out. I had the tranny serviced and sensor replaced over a year ago and it's been running great every since.

 

For those who have a meter and want to check without using a scanner:


This should work on all temp sensors including IAT. I know it worked on Ford single terminal {for gauge} and dual terminal {ECT to PCM}