88 GL-10 Turbo jerkiness

[M45]

Please help me diagnose my 1988 Subaru GL-10 Turbo AWD Wagon with automatic transmission, and help me to fix it myself as inexpensively as possible.

 

It has become quite jerky recently. It started a month or so ago, at about 60 mph or 3200 rpm on the freeway. It will be going fine and then lose power for a fraction of a second and then carry on normally for a few seconds. If I lifted off the accelerator, it would stop jerking; same thing if I pushed up the rpms. It seemed more prone to do this on warm days, but if the first drive of the day didn't have the jerkiness, then the car would run fine even if restarted warm or cold after stops.

 

As it got worse, the rpm band prone to jerkiness got wider and wider until it was hard to drive it over 35 mph. When I drove it last, I could hardly get any power unless I floored the accelerator.

 

Possible causes:

 

1) dirty or broken throttle position sensor TPS. I've heard that some kinds can be cleaned.

 

2) stuttering fuel pump.

 

3) clogged fuel injectors.

 

4) electrical problem, perhaps in the distributor.

 

Only #1 seems to explain the RPM band.

 

Other possibly related issues: I had been getting only about 20 miles per gallon city, and 24 on the highway, which seems low. This may be related to the right rear wheel, which does not turn as easily as the other wheels. Once (after I knew about the rear wheel), it may have gotten overheated after three hours of high speed highway driving.

 

Thanks in advance for any assistance rendered.

[Gloyale]

I would suspect you're ignition system.

 

Plugs, wires, cap, rotor. Can't hurt to change them out.

 

You could test the TPS with an analog(needle) multimeter. Watch for an even change in resistance while openi9ng and closing the throttle.

 

Also inspect the MAF and the tube from it to the intake. Could be leaky or loose. Beyond that, you may have a coil problem.

 

 

20 city/24 hwy seems pretty average for a turbo wagon.

 

Fix that rear wheel bearing immediatley. I've heard (and personally seen) the rear wheel lock up while driving. In one board members case it actually caused him to lose control and flip the car at hwy speeds. Not good.

[Major Lazy]

I had been getting only about 20 miles per gallon city, and 24 on the highway, which seems low.

 

 

I get like 19-23 so with a 5 speed, I think your mileage is OK