Yeah, I have switched back to 91 and notice more acceleration but still get the noise... I only fill up at 76, Chevron, and Shell, never use no name gas (it is hard to find that in Los Angeles anyway)...

Maybe pinging is the wrong word, it almost sounds like valve clatter or lifter clatter, but I just got the oil changed and it isn't using any oil at all. It only occurs in gear (L, I, D, and R) and only under acceleration, IE if I'm costing on the freeway not accelerating the sound goes away.

My MPG's suck (19.5 to 21.5 per DIC) but they have always sucked since day one (I do a lot of heavy traffic driving and a lot of 80mph freeway driving)...

I'm going to get some of the GM Cleaner and see if that helps.

 

sounds like a noisy lifter, but i don't think we should be able to have that problem.

 

For heavy traffic that's really not that bad mpg.

Not a clue about the lifter noise, which is what it sounds like to me.

 

Found the problem, leaking catalytic converter. Fixed for free under the California emissions warranty.

 

Federal emissions warranty is 10 yrs 100,000 I think.

 

Funny.....my car sounds fine when it is cold but after it is warmed up and I give it gas it sounds like a diesel a bit....sort of like a clacking noise when I give it gas...I wonder if it is the cat as it does sound like it could be exhaust related


How did they discover the leak?




Goose

 

Goose, that could be the Cat going bad... I never had a check engine light or anything, but mine got so bad it did it all the time. The service paperwork said they cleared a code so it must have thrown a code but not a CEL. If it wouldn't have been covered under warranty it would have been a $95 diagnostic fee.

Question. Does it make the noise when it is in neutral? Mine would quite down in neutral and park.

Another thing to look for at night after a long drive with highway speeds look under the car and see if your Cat is glowing red... mine was, that is what tipped me off it was the culprit.

 

Is quiet in N and Park...I will take a look underneath tonight after a ride....

That is why I am leery of bringing cars to the dealer..you hear a noise and want to know what it is and they whack you that fee. Quick and easy money for them..and all it takes for them is to go "supposed to sound like that" which is pure BS


So what made you go to the dealer in the first place and what did you explain to them was the issue?


Goose

 

The glowing Cat and the fact it got so bad I could smell exhaust in the cab of the car. But I had the noise for a LONG time before it got that bad.

 

Wouldn't you have a recognized depreciation in fuel mileage?