Bucking, bogging, pulsing

So I was directed here from the second gen page because my car is technically a first gen.... not sure but here it is

 

ORIGINAL POST.

 

94 Legacy 2.2, auto

 

Recently bought this awesome car, single owner, 150k miles. Really love this car.

 

So my car as of yesterday lost power at a stop sign. Did not cut out or anything, noticed CEL popped on so I pulled into a parking lot. The car was “pulsing” at idle. Basically up and down on the RPM, around the 1k mark. Made it home and spent the day testing things out.

 

When I start the car there is no CEL, but driving it up the road it pops on and the symptoms start, bogging at acceleration, stalling and also surging. When it stalls and I start it back up, CEL is off, then rinse and repeat.

 

I was looking on the forums here and tried the three easiest things I could find to do.

 

Replaced fuel filter

Replaced air filter

Cleaned MAF sensor.

 

No chance after that. Was looking for some guidance because this car is great and don’t want to see a bigger issue take it out. Thank you.

 

UPDATE

 

Learned how to check codes on this guy, at first I was only getting 23, but I am now also getting 22.

 

I inspected the knock sensor and found it to be cracked and corroded, ordered new one last night.

Wait until you have replaced the knock sensor and then come back with the result.

 

 

How is the condition of the cam belt and sprockets? If it starts to wear out it might be a risk that it can jump a tooth.

New knock sensor installed, ECU reset, and everything seems okay. No new codes. Success!!!

Awesome!

 

I wonder what the actual mechanism was for that. I guess the crack let the sensor send a lot of false 'knock detected' and the ECU pulled all the timing?

I spoke too soon. Car stalled out on me today threw another code 23, MAF. I decided to clean the electrical plug there and reset my ECU again. Drove for ten minutes, no CEL. Will post updates late today if it happens again.

Yes, MAF and KS are common weak points on these. For others' reference, Get a '96+ white or gray (can't recall what they were originally) used one - just make note of the connector as it changed somewhere around '98, IIRC - it can still be used, just swap it. Subaru updated the part due to the early models' crack-a-lackin'.

 

For the MAF, the Green label JECS or AUTECS from any '90-'91 2.2 Auto/AT and '92-'98 2.2 (non-turbo) or 2.5 AT or 5-speed Subaru used will also work.

 

I've read where the New/cheap aftermarket KS are OK, but I'm not so sure about the MAF.

Edited September 23, 2020 by wtdash