when in 1st gear accelerating, it sometimes decides to spit and spudder at 4k and continue to 4.5k, then run fine, which is really annoying

 

and occasionally it likes to play the same game in the 2k range, which is very bad, because I am always in the intersection, so I have to wind it up to 3k to dirve off

timing is set @ 20* fuel level is @ 1/2 ambient temp is 0c engine warm

why

 

'89 rx

 

maybe it just wants an oil change

mine does the same thing , between 1st and 2nd gear , i call it a dead spot , but i have 193,000mi on motor , 88 dl d/r wagon

how old are your ignition components (cap/rotor/plugs/wires, etc)?

 

After that, I'd guess that the TPS has a bad spot(s) in it.

 

I recently got rid of some low speed bogging I had by replacing the TPS with a junkyard one.

Hmmm, same here -- with about 400 miles on a rebuilt engine, new plugs, plug wires, oxygen sensor, EGR sensor, EGR valve, fuel pump and suchlike.

 

Starting from a stop sign, it's erratic, better with the gas pedal pushed down, but the electric hybrid or other little car in the next lane always pulls away from me easily in the intersection.

 

This is a 1988 GL non-turbo 5-speed wagon. Still being broken in, obviously. But I assume the fuel injection system still has 240,000 miles on it, just the engine was rebuilt.

 

I've been imagining maybe the (single) fuel injector is dribbling.

 

I confess I have no clue what a TPS is. I tried to look it up and found airplanes with Subaru engines, here: http://www.sdsefi.com/

 

Some of their stuff sounds good, but .... anyhow.

the Throttle position sensor (TPS) is a little black bock on the side of the throttle body - it uses a variable resistor and a switch to tell the computer where the throtte is - I think there is a very specific proceedure for replacing them (switch position at such and such clearence .... ), but I do not know what that is - any service manual (FSM, chiltons, haynes, etc...) probably has it

 

I agree that it is probably your problem if you have over 200k on your FI system, and the engine has been rebuilt, and you have new plugs, wires, etc - that is just about the only other thing that really governs the engine durring acceleration - the only other thing that remotely comes to mind is the MAF (mass air flow) sensor (attached to air filter housing)

Here's the procedure to test the TPS http://www.ultimatesubaru.org/forum/showthread.php?t=24997&highlight=throttle+position+sensor (well, a pdf in that thread)

 

If you want to replace it and you have AC....

I found it was easiest to take a file and make some clearance on the AC compressor. You only need about a quarter inch off the corner of it to be able to slide the TPS off, versus removing the fan, alternator, unbolting the compressor, so you have 1/4" of clearance.

 

You/your mechanic will see what I mean when you look at it.