Strange hesitation on '87 Turbo Wagon

[sandman]

I have an '87 Turbo Wagon with this strange hesitation. Half of the time it runs fine and the other half its like a good amount of travel on the gas pedal is not doing anything. You go to accelerate out of a corner and nothings there. If you floor it, it takes off. Here is what I've done:

 

- Complete tune up. Plugs to the Rotor and air filter.

- Checked timing.

- Changed oil and replaced the oil pump gasket (had the "tick").

- Adjusted the TPS. The screws were loose on it and it had a bottom end dead spot. Different from the current problem.

- Gutted the Cat.

- Cut the bottom of the air box and removed the intake muffler.

 

When I adjusted the TPS I noticed that it was at 0 volts at idle and then jumped to ~4.5 volts when it was moved some. Others that I have setup have been more linear to actually show where the throttle position was. So does this sensor just tell the computer that the throttle is open and the MAF handles the rest? Or do I need another TPS?

 

Thanks.

[DerFahrer]

It could be the TPS, but if it isn't that, I'm almost 100% sure I know what it is.

 

It appears that Subaru injectors are quite easily clogged up. I ran my XT once to the very last drop of fuel in the tank before I filled up (about 50 miles with light on). After that, the car had a hesitation very similar to what you describe. My theory is that the sediments at the bottom of the tank that I was running on probably made their way through the fuel system.

 

I had been chasing the same problem on my Legacy for YEARS, trying all sorts of fixes that had been successful for others. And then someone told me to try a fuel injector cleaner called Lubro-Moly Jectron. It's a German made product, and many VW/Mercedes owners swear by it. I ran 3 consecutive tanks with a bottle of it each time in my Legacy, and that did more good than anything else I had tried. I managed to run 1 tank of it in the XT before I had to put it down for repairs, and just that tank showed an improvement.

 

It's hard to find that stuff, but just type in that name in a Google search and you'll find a couple online shops that sell it.

 

Good luck!

[iluvdrt]

i am haveing the same problem in my 87. i tried all kinds of fuel injector cleaners, including denatured alcohol, and seafoam.

 

if anyone figures it out let me know, as i am giving up. i have tried everything.

 

on a side note, sandman did you notice any gains with the gutted cat?

[sandman]

I'll try the fuel injection cleaner as it might need it anyway. Thanks for the suggestion.

 

I have access to another motor and sensors, Maybe i'll take some readings off them and see what I have.

 

On the cat, Maybe some, I mostly did it for the MPG gain. I also plan on tweaking the turbo in the future and did not want the restriction.