Engine bogging, hesitating

[TomInOR2002]

My 1987 GL-10 (EA82T, F/T 4WD D/R 5 speed) has been acting up for awhile and now it's getting worse. It bogs down and acts almost as though one or more cylinders are misfiring. It seems to act up almost randomly, but it seems to happen more often in 3rd, 4th and 5th gears, on hills or when passing (basically whenever it's under a load). It can also happen when just cruising along at 55 mph on the highway, though. The engine will also cut out momentarily when passing or going up a long hill very similar to overboost cutout. Does anyone know where I should start troubleshooting? I've changed the fuel filter, spark plugs, distributor cap and rotor, air filter and PCV valve. I've also removed the catalytic convertor under the car. I have been thinking that it's either fuel starvation or a plugged catalytic convertor, but I don't have the money to keep shotgunning the problem. I will pull the codes tonight, but does someone have an idea what else to check?

 

Thanks,

[Skip]

Tom, my 87 turbo just went through a very similar problem.

When the bog ocures look in the rear view for signs of black smoke.

All my problems were very like yours.

 

Problem - the connection to the intake throttle body is loose.

This is the rubber connector pipe under the intake plenum (Al part that has "Subaru 4wd TURBO" cast into it.)

May look tight but try to lift it up by hand.

What was happening was when the boost pressure got high enough the part was separating and allowing the boosted air to leak out .

Same fuel squirt, less air => rich mix

Hope this helps

 

BTW no error codes will be displayed for this problem.

[PHATBRAT]

Yeah, I once had a similar problem too, It was a vacuum line. Took me forever and a damn day to find it. Strange that it was intermittant. It also made for hard starting at times. Boz