Sounds like a diesel on accelerating

My 1999 CVPI, has taken to start "pinging" almost sounds like a diesel engine when I accelerate with the a/c on after the car is warm.... If I shut A/C off, it's fine... It's fine at idle, fine in park (even revving)...

Any idea?

Do you have anyway to check the PIDS on the sensors? Sounds like the MAF is not reading the amount of airflow correctly making the PCM deliver the wrong amount of fuel. You can try cleani9ng the MAF(very carefully) with electronic cleaner on the hot wire in the sensor. Be careful not to break the little wire. See if that helps any.

It's just weird that it's ONLY after it's warm, and ONLY with A/C on.. No other time.. I don't know if it makes a difference or not, but the car was sitting for a year after a blown plug, I bought it from the lady and fixed the plug.. Changed the oil, just haven't gotten to any of the other fluids..

I will have the my brother check it though, and let ya know.. In the meantime, if there's any other ideas, or if this info gives any other clues, lemme know..

Well, I seem to have stumbled across the problem's solution. Upon checking the coolant reservoir, I noticed it was clear, and low.. added water, and anti-freeze to it, to the full-Cold mark, and it SEEMS to be doing fine so far... but we'll see