gsta127

iTrader: (1)

I own a manual 93 sc300 and was hoping someone could help me figure out whats going on. So whenever I start up the car from a cold start the engine stutters, not terribly bad but enough to make the rpms fluctuate slightly and enough to make the whole car shake and vibrate at idle. Usually after driving around for about 10-20 minutes the car starts running normally again and smoothly. Before this happens, when accelerating, the car somewhat jerks back and forth and it feels as though I only have about 50% power. Also while reving up the engine, it isn't smooth like normal but instead its really rough. The idle is rough enough in fact that someone asked me if I had aftermarket cams installed. I noticed too that the exhaust note, have borla muffler installed, at idle is a bumpy put put put , instead of a smooth note like normal.

After searching around I have come up with some possible problems,
Clogged Cat (although the car only has 98,000 miles)
ECU problem (check engine light has not come on though)
Something wrong with the cam timing
I installed BFI, maybe its not getting enough air
Possibly spark plugs or injectors need to be replaced

Any information you could give would be greatly appreciated this as been bugging the hell out of me for the past month or so.

Additional information: It feels that I have lost some top end power, whenever Im driving on the freeway at 70 or so and there is a slight upgrade I have to down shift to 4th and floor it to accelerate at all. Im not sure if this is a problem, or just the lack of power from the 2jz-ge.

BlackEJ8

I had a very similar problem and I traced it down to a disconnected vacuum line, plugged it back in and it ran perfect.
I would also check plugs/ignition system