mpe488

ok, I wrecked my TA about 3 months back and jsut got it back from the shop. I noticed it seemed to missfire every few second and the engine would sort of twitch alittle and I could here a sputter in the exhaust note, but I didn't think much of it. But it hasn't gone away.

I thought it mighta been bad fuel sitting in the tank for 3+ months, but I have run it down to E and refilled it half way twice already. But the engine is still sputtering, although not as badly. However, it's running very slow. I think it's running slower than it was when I first got it back from the shop (and the sputtering was at it's worst. I dunno if they are separate problems.

But just to put it in perspective- I first raced my friend v6 mustang from a 40 roll and immediately whored it, but now even from 25 (my best spot) he pulls up ahead and the TA has to play catch up.

Does anyone have an idea what the problem could be? This is really worrying me.

Syxx613

iTrader: (8)

take it to a reputable shop, maybe even a dealer. there are way to many shitty shops out there that dont know what to do with an LS1.

02SS#406

iTrader: (1)

Start simple...fuel filter? MAF? Mis-fire? Air/vacuum leak?

RPM WS6

iTrader: (3)

First thing I'd check/replace, based on your description, would be plugs/wires.

mpe488

the plugs/wires have 3,500 miles on them, so I just checked that they were all pushed in snugly. And I put some treatment in the tank to see if it could clean out the filter if that was dirty from the bad gas. My bro just took it out for a drive after letting it sit a bit, I'll let you guys know if it's better.

RPM WS6

iTrader: (3)

Have you gotten any SES lights? Do you have access to an OBD scanner of some sort?

Also, do you have access to a fuel pressure gage?

98hardtopZ

iTrader: (7)

could the shop have put 87 in it? wouldnt that cause it to run shitty and switch to low octane timing tables?

mpe488

no SES light, and I don't have a scanner, so I dunno fi it;s throwing any codes. It can't be 87 octane because we've refilled with 93 enough that less than 1% of the old gas is in the tank.

After the fuel treatment the car is still running badly.

And now that I remember events, I'm almsot positive the car's condition deteriorated after we got it. Because the first few 65 pulls we did were as strong as always, now it falls on it's face from almost any speed. I was thinking maybe slipping tranny... because the apparent missfires got better as the car got slower. And the engine sure sounds like it's running strong, but doesn't.

Any more input is much appreciated, I'm very worried for the car.

mpe488

I think it was a spark plug that was dead- it was the one on the left side all the way at the back, I couldn't rech it to make sure it was plugged in right.

I'm releived that it was only running on 7 when the M3 and the Lightning beat it.