The car is 1993 automatic FDRX7. I was driving my girlfriend's car to school the other day, when a odd problem started happening.
When you press down the accelerator past a certain point, the car feels like it stops, or cuts out, and decelerates before normalizing again. It's like a surging motion. I still hear the turbos going while this is happening, and it does it in all gears of the automatic transmission. I suspect a vacuum leak or a dirty fuel filter or busted fuel pump. Has anyone else encountered a problem like this, and if so, what was the cause?
Any advice appreciated, T/W

 

Lots of possibilities.

If this happens only as your tach passes by 3k rpm, sadly, it's normal. It's called the 3k hesitation and it's an issue with any stock or piggyback ECU. You can search for more info, but few people can ever *solve* without going to a whole replacement ECU.

First change the plugs. These cars destroy plugs enough that it's almost never a bad time for new plugs.

Next find out when the fuel filter was last changed. 20k miles or 2 years is conservative, but not really a bad idea.

There may actually be an injector problem. Look closely at the plugs to see if one rotor is different from the other. I had an injector problem once and it behaved exactly as you described. In-tank injector cleaner isn't a waste of time, but if this is the problem then you probably won't solve it until you remove the injectors and get them ultrasonically cleaned.

The TPS is another reason for bucking and stuff. There is a link in the FAQ to check the TPS calibration.

Dave

 

I don't think it's the 3kRPM hesitation, because it abruptly just randomly started doing it after not doing it the previous day.
I'll look into the other stuff, thanks for the advice!
T/W

 

If the problem wasn't there yesterday, I agree that you should look for loose or popped vacuum hoses.

TPS, injectors, plugs, fuel filter, etc don't tend to go to crap in just one day.

Dave