I have an 89 Firebird TA, 5.0L, TPFI engine. My brother in law had the exact same car. I take meticulous care of mine and he didn't. Yet I continue to have something that sounds like slight pinging with any acceleration. It gets loud on hard accel. I use Rapidfire plugs and they were checked last year, they're about 5 years old. I only put about 4-5,000 miles on the car per year. I also hsd the injectors Motorvac cleaned last year. My air cleaner is a new Fram. Timing is ok. I used to use 93 octane but switched to 89 octane gas. I didn't notice any change in the high pitched clicking sounds.

The shops I've gone to don't seem to do a good job of getting rid of the clicking and high pitched hissing I hear on accel. If it goes away, it comes back in a few weeks.

My MPG seems less than it did a few years ago, and it has seemed sluggish to me. It did better a few years ago before this area switched to gasohol, so I assumed the lower MPG and slower response was due to that.

My brother in law recently drove my car and commented that he had to push the accelerator down more than on his car to get a similar response.

Anyone have any ideas what might be going on? Does anyone have any suggestions? Thank you.

 

Fuel filter?

 

For one, mixing gas is not a good idea. If you changed from 93 to 89, without completely or nearly running out your tank of 93...pinging will occur if you have them mixed.

I tried 89 in my car, and it did not like it at all, same reaction you are having now.

 

The fuel filter is only a few years old, but I guess it could need changing.

I've used 89 octane gas for quite a few months. I usually use Mobil or Marathon brands.