Have you ever ran it with 87 octane? I got my tune in this weekend, and I have 1/4 tank of 87 octane left in the tank and i gotta gradually accelerate, if I punch it the motor pops and slowly goes back down to idle on it's own, even if I give it gas it won't raise back up.

 

I've datalogged cars with an agressive tune running 87 oct. You could see a constant spark retard. But, not the symptoms you are describing. I'm wondering if you got a bad tune?

 

Drain the tank and fill with premium. Your tune has higher spark advance than what can be supported with 87 octane gas.
After refilling, if the problem still exist you may need another tune or there may be some other issues as noted above!
If you continue to drive it, it "should" work ok for cruise and normal light accel but not WOT. If its doing this at cruise and other non-WOT operation I suspect something else is wrong. Usually tuners only add spark while in PE mode or the upper rpms of the spark table when at 90+ MAP KPA.
That poping is spark retard/knock which is not a good thing at all....damage bearings and more.

 

Yeah, I took a 3 mile cruise earlier and it drives OK, but when I punch it (WOT), it will pop. I can rev it as high as I want if I gradually accelerate, but I can't hit WOT.

I was thinking it could be the gas. I have no service engine light, so I'm not sure what else it could be.

 

If you only have 1/4 tank of 87 left. Just fill the tank full with 93 or the highest octane availible in your area.

 

Exactly what I would do. If you have the premium gas tune and are only running 87 octane, it is not a good idea to automatically blame the tune as being bad.

 

i wouldn't be doing any wot revving until you at least got better gas in it for sure

 

I thought nowhere in my mind that the tune was bad.

 

Dude, don't beat on your car with crap gas in it. Are you trying to pop a head gasket, or crack a piston?
You should never have 87 octane in an LT1 regardless of the tune.

 

dump some octane booster in it for now, get to a gas station and fill it up with premium, this SHOULD solve your problem, unless (like mentioned) you have a bad tune.

 

Octane booster won't get you anywhere. See if you can find a local gas station or speed shop that sells Sunoco 110 octane race fuel and put about a gallon in there. That should fix all your problems.

Had the same problem with bad 92 octane gas from Citgo. Added a couple gallons 110 octane, problem solved.

 

What Sunoco unleaded gasoline is rated 110 octane (R+M)/2?

 

This reminds me of a friends who had a blown 4.6 Cobra back in 1997. The cheap bastard would run 87 octane and stay out of the throttle. When he would take it out for racing, he would put premium in it.

That worked fine until he took it in to a dealership for some simple warranty work and got it back with a broken ring land. The mechanics probably had a nice time at lunch.

 

I never had any problems running 87. I ran a 13.9 with just a full exhaust and a 2.6 second 60' on 87.

This was in May of '05. I saw no reason to ever start using premium.

 

Over 10 to 1 compression is a good reason to run premium. I would bet that your ecm may have been pulling timing out. Your chances of detonation are pretty high with 87 octane. Your knock sensor would see it and pull out timing, costing you power.