Dear Subaricans,

 

The problem I've reported before persists: some times it drops RPM by about 500 rpms for a sec or two, gas pedal feels spongy. Then it comes back to normal.

If I drive slowly at that moment (small rpms) then car just stalls and on next start AT TEMP blinks. When I read the codes from TCU -- it reports 23 -- lost speed signal. That code doesn't come up if car doesn't stall - ie if rpm was high enough to don't stall really.

 

TCU doesn't report any codes in any situation. No Freeze Frame data (now I have OBD-II interface :-P)

 

Please advise on what to look for. I've mentioned that it mostly happens if I have a lot of sharp starts and sudden stops, like if I drive in a traffic jam for instance. Once it was right after I started a car and tried to speed up almost rapidly (right after I left parallel parkin spot) -- pedal became spongy for a sec...

 

May be I should monitor some parameters I can through OBD-II? I'm not sure if that would help though :-/

please don't be shy, please any advice or idea are welcome ;-)

I have no clue what to start from

it seems to be happening more during more of sprited driving or just driving in a traffic jam, ie when there is a lot of rapid alternation between gas and break. Some times it just happens right after I depress gas pedal and then switch to breaking...

 

Please advise on what to look for???

What do you mean the gas pedal feels spongy?

 

If you can monitor data, that would be a good way to try and determine what's going on.

 

Can you monitor more then one thing?

What do you mean the gas pedal feels spongy?

That 1. "resistence" of the pedal drops, ie you can depress it with smaller pressure applied than usually, 2. depressing it more doesn't really react in immediately increased rpm

If you can monitor data, that would be a good way to try and determine what's going on.

Can you monitor more then one thing?

It seems that I can but then sampling rate of the other parameter will drop correspondingly. Which parameters would you recommend to monitor?

So basically pressing on the gas pedal doesn't do anything to affect engine rpm...

 

 

Well I would probably start by monitoring the vehicle speed sensor 2. See if the signal cuts out as to cause the loss of signal issue.

spngy pedal could be caused if there is a detent cable. check to see if yours uses one. but i am prettys ure they have ben using all electronic ones for awhile.

 

if it constantly stalls try this, try to put it in nuetral when braking(helps save your brakes also). this can be done without pushing the button (iff applicable). N-D is always unlocked in case of sticky throttle or quick start after engine dies on rd. if you push the buttom you may jam it into reverse...whihc is NOT GOOD.

 

good luck and keep us posted

 

Joe

Thank you Joe AKA scoobdude for ideas

spngy pedal could be caused if there is a detent cable. check to see if yours uses one. but i am prettys ure they have ben using all electronic ones for awhile.

 

It seems to be not a cable issue because generaly pedal feel is ok. It gets spongy just during that rpm drop

 

The problem seems to reappear more often with each week. Also interesting fact: today I was driving maitaining speed around 30mph and then without any slow down feel of the car (ie rpms probably were fine) I felt spongy pedal and saw that RPMs are about 100-200 ie almost 0. I depressed it more and it may be that caused it to don't stall but come back to normal rpms

 

Can it be somehow linked to transmission? or I can rule that out because really I seems to don't loose the gear. But this problem start appearing after I overfilled transmission fluid a bit after I drained it... I'm just thinking what could I bend/disturb for this problem to appear...

 

good luck and keep us posted

I will be more than happy to do so :-)

I had similar issues with my legacy where it would just stall/lose power. It ended up being the MAF sensor.

 

I didn't ask, but have you done any intake modifications?

I didn't ask, but have you done any intake modifications?

 

I didn't but I believe I've changed air filter at that moment after which it start occuring... then later on I was cleaning MAF sensor as well... There is one of the wires which is too twisted as to me but I was trying to kinda "mangle" a bit and it didn't react to that. Also I don't have any codes stored about MAF, which I would assume should be there if it is MAF. Did you have any codes? I will try to monitor MAF signal as well to diagnoze the problem

My problem was very intermittent, and most of the time I would not get a cel or any codes stored. I battled the problem for over a year. It finally left a code, which confirmed my suspicion about the MAF sensor.

 

What did you clean the MAF with?

My problem was very intermittent, and most of the time I would not get a cel or any codes stored. I battled the problem for over a year. It finally left a code, which confirmed my suspicion about the MAF sensor.

Hmmm... Actually there was a code about MAF loong ago, but indeed after the problem start appearing... It came together with the code for oxy sensor I believe. But then I changed oxy sensor, cleared out the codes and MAF code never came back, so selfish/blind me - I rulled out that possibility of bad MAF

 

What did you clean the MAF with?

Some electric parts cleaner with no residue guaranteed. I even didn't take it out of the box because the screwes are too rusted and when I tried to extract one of them I just broke its head. So I took the sensors "in the box" and sprayed with cleaner from both sides, let it dry and placed it back in. What I'm thinking bad about is may be one of the wires - it was too bended - may be it is bad... but tweaking it more didn't influence engine while it was idling...

 

I was trying to monitor parameters while driving this morning but the interface I'm using is not chipped one, so computer kept loosing the connection and it didn't capture the single moment when the thing happened so I still can't say what MAF was saying at that point. I will try to do the same on the way home.

Dear Subaricans,

 

some times it drops RPM by about 500 rpms for a sec or two, gas pedal feels spongy. Then it comes back to normal.

If I drive slowly at that moment (small rpms) then car just stalls and on next start AT TEMP blinks. When I read the codes from TCU -- it reports 23 -- lost speed signal. That code doesn't come up if car doesn't stall - ie if rpm was high enough to don't stall really.

 

 

Just started getting the same problem!

 

Fired it up this morning, let it warm up 2 or 3 minutes, and took off down the road (35-45 MPH city driving). I get to the first stop light and a BAD missfire (all 4 cyl cut at once) but it recovers. Couple miles later it starts really cutting out, coming back, and I feather the throttle to keep it going. Pull into a parking lot and it dies. Restart the car, AT TEMP light flashes 4-5 times, I pull into a parking spot and shut it down. Take a quick look at everything, fire it back up, seems OK at idle and rev'ing up in park so I take off down the road again.

 

Starts cutting out real bad once again and I start working the throttle to try and keep it running but she eventually stalls. Really hard to get her started this time but when it does the AT TEMP light flashes a few times and away I go (on a busy street; gotta stay moving!) She behaved her self the last few miles home.

 

No check engine light. Scanned with cheap ODBII scanner and no codes. Sometimes at idle, in park, she gets that bad missfire (seems like total loss of spark or fuel; I mean all 4 cyls cut) but doesn't stall. Knock sensor was replaced last year. Used CRC MAF cleaner and cleaned the MAF but problem persists. O2 sensor changed almost 2 years ago. She runs real rich; on a cold start you can't miss the smell of fuel from the tail pipe. Mileage is a sad 24 to 26 MPG (mix of highway and city)

 

Any ideas other than standard reply of 'spark plugs and plug wires'? Got that one covered; lets try some real troubleshooting =)

Flashing AT Light = codes stored in TCU.

 

Loss of speed sensor (OPs case) can cause vehicle to go into limp mode that can result in bad performance and poor fuel economy.

 

Best to get the codes from TCU (there is a post somewhere here on how to get the codes from the TCU but it may be for newer models?).

Just started getting the same problem!

apparently I've forgotten to follow up with the resolution in my case -- indeed was MAF sensor -- replaced it and problem was gone, car was sold a year after or smth like that ;-)