PSUstanghunter

I own a '99 SS with the STS rear mount kit making a comfortable 10psi. I've noticed lately that the car will make full boost, but then around 3300 rpm it will buck. Also every now and then when i hammer it, it throws out black smoke, alot of it. Ive never had any problems with the car since I purchased it. I was wondering if you guys had any thoughts before I haul it into my mechanic and spend a ton of cash i dont have right now. Thanks in advance.

Smearin

Holy Richness Batman!!!

Whats your a/f ?
what size turbo?

Sounds like your running rich.... real rich....How much smoke?

I was gonna say choking the turbo... but at 3300.. hmmm

maybe your tires are just spinning and then your hooking?

PSUstanghunter

The car has been running fine though, it was tuned. It's not spinning the tires. If I mat it it bucks like 3 or 4 times then goes normal. Someone help me out here

Smearin

Do you have a wideband? whats your a/f? What size turbo? any unusual sounds coming from the turbo?

Anything to work off here?

PSUstanghunter

I have a wide band, the a/f doesn't look any different than it normally does. The turbo is a t-76.. nothing sounds unusual something specific I should be listening for? Please help guys

PSUstanghunter

You could probably also consider the "buck to be a hesitation? It does it 2 or 3 times around 3300 or so and then things kick in and go.

turbolx

$10 says spark knock nearing peak torque/cylinder pressure...

Frost

iTrader: (45)

What does the wideband SAY? Are you on a stock bottom end? What is actual timing at the point of bucking? Do you have a set of colder plugs in the car?

PSUstanghunter

Aside from the fact that it may be running somewhat rich, is there a possibility that stale gas could cause the bucking/hesitation?

Smearin

Whats your a/f @ WOT? Are you running premium? What plugs are you running?

JD_Z28

iTrader: (19)

You could be burning oil. Have you checked your resistor and cats.

PSUstanghunter

Ok guys, I put some fresh gas in the car today and drove it around.. It is now appearing to be running fine. I think I may still be a little rich, which I will go get a dyno/dynotune done to fix that. I let the car rest a couple of different times for like 2 hrs the first time and like 6 the 2nd and it is running just fine and dandy. Odd.

PSUstanghunter

and correction i have a narrowband a/f guage.