for starters here in vegas 91 octane is the highest octane available, unlike 93 octane in other areas of the u.s. i run 91 in my 2000 coupe and it pings under load when i climb hills, etc. i though i bought bad gas or the local station i buy my gas from is ripping people people off but i have tried other gas stations and it hasn't gone away. shouldn't the knock sensor retard the timing or could my knock sensor be bad. no lights or codes or alarms are present. all feedback/suggestions greatly appreciated. thanks.

 

Do you have a cold air intake?

Do you have a oil catch can?
Do you have evidence of oil mist from the valve train getting into the intake manifold?

my recommended first step would be to decarbonize your engine...
SeaFoam or GM top Engine cleaner and see if that alleviates the problem.

The second step is find a tuner in your area,

 

the car is 100% stock

 

The only thing I can tell You, is that when I was "out West", I had "pinging" as You said.

When I returned East and got some 93, it went away.

I have a Blackwing intake, otherwise stock engine wise.

 

im from the land of 93 octane and sunoco ultra 94 ny/nj/ct tri state area and when i was palnning on moving to vegas in 04/05 i noted that 93 octane was available here at the time and that has since changed and i have no choice but to get 91 these days

 

I've been fighting the pinging issue for a long time in my '99. One thing that did help was using the GM Top End Cleaner which is similar to SeaFoam. Another help was getting the latest software/firmware updates programmed into the car. Prior to those updates, I had it tuned, but it didn't help at all. Tune changes were lost when the new programming went in. Replaced the knock sensors, cleaned the MAF several times, plugs, wires and etc... Found that when I use Sam's Club premium gas, its worse than other brands of gas as far as pinging goes...why is unknown. I'm going to replace the front O2 sensors here probably next week when I receive them from GmPartsHouse.com, in hopes that it will help. Per the manual, they are supposed to be replaced at 100K miles... I think it said. I'm way above that mileage and they are still stock. Does anyone know how the rear O2 sensors effect performance or are they just there to measure the after emissions for a sanity check?

 

anybody know why certain regions only get 91 octane instead of 93anyhow???

 

I noticed a slight ping at WOT after I installed my vararam. I changed the plugs and wires to make sure they were not a problem then I decided to purchase the Predator program to see if it would help and it did.

If you have a lot of carbon build up in the cylinders (top of pistons and valves) they will require a higher octane to overcome this buildup. I use Chevron Techron fuel system cleaner in all my vehicles every 3 or 4,000 miles and I never have any problems with carbon buildup or pinging (been using techron for 16 years now the same Jeep). You may try TWO treatments back to back to ensure a clean combustion camber.

You could try an octane booster to see if it will help but read your owners manual – it warns against a specific additive that is found in most boosters. Also most booster say they will raise your octane by 10 points but in reality the 10 points is = to 1 octane (so 91 = 92 now) but it might help you.

We use to have 93 everywhere in AR but now it is very hard to find. When I find a local station with 93 it seems like a month or two later they switch to 91 and sell it for the same price. 93 is available in other major cities in AR so I think it’s a matter of the local stations buying the cheaper 91 and they sell it for the same price as 93.

Good luck.

 

Probably has something to do with altitude. The higher you go, the less octane you need since there is less O2 in the air.

 

This is a good post. I am having the same issues with my '98 coupe.



LO PHAT

 

I just took my stock 01 (M6) out of storage and noticed pinging/knocking at high rpm. Does the gas lose octane if it sits for five months?

 

In a metal container, octane dissapates 1 point per 30 days. Plastic is worse. So your 91 over a 5 month period is now 85, with a minimum of time lapsed you have gunk instead of gas.

Thats what GM trained us on in the mid 90's. We were supposed to tell customers one tank minimum every six months to keep things fresh. Get out and drive her

BTW, I have 14K on my 04 and have already had the intake off to clean the oil and crap out once. I am sure after a few parade high-rpm's and some HPDE spirited driving I need to again. Guess driving it hard once in a while keeps the engine clean (even if the intake is not!).

HTH,
Cassidy

 

I have the same problem. Every trip to SoCal it runs its *** off then get back to Vegas and the box of marbles returns. Before the
CAI & cat back it would do it also so that cant be the problem. I was thinking about replacing the knock and 02 sensors for the hell of it as well as mine is not throwing any codes currently. I need to do something before I grenade this thing before we hit 100 degrees in another month.