Mitsubishi Repair: 1992 mitsubishi 3000GT SL MANUAL, coolant temperature sensor, crank angle sensor

Question
i have a 1992 Mitsubishi 3000GT SL 5-speed manual. Now my problem is when I'm driving and the cars is warmed up the check engine light will come on, then my car will feel real heavy and no matter how hard i push the gas the gages won't let me get past 2500 rpms. Also when I'm idling at a stop light my gage will jump up and down, an I would have my foot on any pedals. But like I said when I'm driving it feels like my car is heavy and either there is too much air or not enough going to the engine. When I push in the clutch the car wiil go back to driving fine until about 3 mins later the same thing. Please help me.

Answer
Phil,
This problem can be caused by any number of tune-up items.  Bad spark plugs and plug wires are usually the initial culprits that should be replaced.  You should have your Idle Speed Control (ISC) motor inspected as well.  That controls the idle of you engine when your foot is off the accelerator.  Here's a general list of problem items that could be behind your problem:
- Bad plugs and plug wires
- Faulty ISC
- Faulty TPS (throttle position sensor)
- Faulty engine coolant temperature sensor
- Faulty cam/crank angle sensor
- Worn timing belt
- Worn fuel pump
- Clogged fuel filter
- Clogged air filter
- Blown intake gasket
- Vacuum leak in intake line or hose
- Clogged PVC valve
- Clogged catalytic converter
- Faulty oxygen sensor
- Clogged or faulty emissions component

As you can see, there are many items that can cause this problem.  I would recommend having your local mechanic give it a tune-up.  If that fails and your mechanic as at a loss as to what else it could be, have the dealership take a look at it.  The 3000GT is not a very common car and many local mechanics do not have the experience on them that a dealership mechanic would.
Good luck!