Noobie Needs Help on 99 gtp

[Jm1020]

Hi
Im new here and well i already need help Well today i got my 99 gtp and i was so excited, and my girlfriend wanted to borrow it to go to work. And i said fine since she had been driving me everywhere while i was trying to get this car. And she tried to be really nice be filling my tank up but the only problem is she put in 87 gas Its not her fault cuz she didnt know but im just wondering will it affect the car right away or will it be ok just this one time, or should i start worrying lol. Any suggestions would be greatly appreciated.

[BNaylor]

Run out as much as you can and then put in premium. Mixing the two different grades will not hurt. Don't get it on by doing any heavy acceleration or WOT to preclude any possible knock retard (KR) and you'll be just fine.







Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[richtazz]

your mileage is gonna suck for a while, but other than that, don't hot rod it until you get that 87 octane out like Bnaylor said

[bbrock]

lol, My wife did the same thing to my 05 GTP last week. Has a pretty dramatic effect on performance. I didn't know that my wife had done so and I went and drove it. I was pissed at first because the car only has 1000 miles on it and it wasn't driving at all like it had before, thought the dealer had snuck a lemon in on me. All is well now though.

[BNaylor]

A good friend of mine let me borrow his Cadillac STS with Northstar V8 a few years ago and the keys to his condo when I visited Orlando, FL and Disneyworld. I topped it off with regular unleaded when I returned it.

I didn't tell him about it until a few weeks later. Needless to say he never let me borrow his car again. I guess he got pissed off. Oh well.






Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[mike561]

yea ive herd from a few ppl on here that its ok to do that, just not to continually put in the 87 or you can risk long term engine damage.

[regalfriend]

In some areas 100 octane(unleaded) Cam 2 is available. Whatever room is left in tank , top it off. Just try to dilute the low grade with Premium as much as possible. 87 octane wont blow your motor, especially since it has been mixed w/ some 93 octane...You just want to accelerate very light untill your sure you got all the crap out.

[stlwagon]

You'll be fine. My wife has done the same to me before. Just don't step on it until you burn off most of the 87 and refill with 93.

[justav6]

What?!! i didnt know all this! these cars need premium? thats not what i wanted to hear.

[rbsteve]

no worries about mixing the grades of fuel. Thats what they do at the pump anyways. Gas stations usually have one tank of regular 87 and one tank of premium (91-93, depending where you gas up). The middle grade is just a mix of the two that occurs as you pump.

BTW you say that a GTP needs premium, but is an SE ok on ordinary ? thats what ive always run mine on.

[richtazz]

Only the supercharged engines need premium fuel, the 3800 and 3100 run perfectly well on 87 octane.

[muff34]

Hi Rich I have been told that the only difference between the 3800 and 3800 s/c is the supercharger is this right?. The car I am looking at is also `99 GtP s/c .Previous owner says she run mid grade fuel ,once in a while throwing in a container of injector cleaner. 28 MPG highway 162,000 kilometers on it seems to run very well. Not trying to be smart but what exactly is the potential problems ,must be s/c related and if so can it not be bypassed. I have read other posts where people have taken the belt off and have also heard that there is a kit for s/c to bypass it. I Know that nobody with a supercharger wants to neuter them but with higher fuel costs etc ??? Ya I know probably shouldn`t look at the car but with all the bells and whisltes on it it is hard not too.

[richtazz]

My mother in laws 04 Park ave Ultra only gets about 22-23 highway MPG with 87 octane, and it shotup to 28-29 with premium. She's never tried mid-grade, but the owners manual states to run 93. The biggest issue with lower octane is KR (knock retard), which saps power and mileage. If you're a lead foot, or want to mod the car, stick with premium. If fuel costs are your main concern, find a GT without the supercharger. My GT gets 23-24 city and better than 32 on a trip and purrs like a kitten on 87 octane. If the previious owner got that kind of mileage on 91, then it sounds like you should be ok on 91 octane. The problem in Michigan is that mid-grade is only 89 octane, and still causes KR problems.