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1991 GT BAD Hesitation/Cut Out problem


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I just bought a 2001 Legacy GT Limited from a non-car guy who got fed up with it for $500. The car has a lot of miles on it 240k but is in nice condition. It's had a new tranny (auto) and new head. It runs perfect except....and this is the reason he got rid of it, It sometimes/most times studders/cuts out when tring to accelerate, even mildly. It feels to me like a spark plug problem/cylinders cutting out. But, the guy had the dealer replace the plugs and wires and it didn't fix it. The mechanic recommended changing the air/fuel ratio sensor next. But the guy was sick of spending money on the car and sold it to me. Someone suggested to me cleaning the Mass air sensor. Is that the same thing? Any suggestions? The car at times has full power and runs smooth which leads me to believe it is an electrical issue.
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Try one of the Tuners in the tuning forum.

 

I have no idea, but maybe one of them can connect to your OBD2 port and do some datalogging.

 

The MAF sensor can be cleaned by spraying it with Carb Cleaner from the auto parts store, while the car is running or not.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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  • 2 weeks later...
Still having this problem. It does't cut off it's power just cuts, then by feathering the gas it will"find itself" again. I tried a new coil pack cause it seemed like cylinders were cutting out but that didn't help. Someone suggested a clogged Cat, but the exhaust doesn't sound constricted. I took out the front O2 sensor to see if that made any difference, but no change with it out. I also thought that releasing some exhaust through the hole might help troubleshoot the clogged Cat idea. I'm stumped. How would the TPS cause this? Can it be tested? Any other ideas?
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Is it a 1991 or a 2001? The title says something totally different from the beginning of your thread...

 

Either way, start with the ignition and work your way from there. Spart plugs and wires are probably the culprit. Next would be clogged fuel filter/fuel injectors. Also check the O2 sensors (Remove them and spray with starting fluid then reinstall). It could also be a clogged catalytic converter (Remove the bolts holding it on to find out. Leave a small gap between the cat and the pipe. Don't do this if you live in a "Gated Community" your neighbors Will call the Ponine...). There's only one way to find out... Gotta check everything.

 

The TPS would make it hesitate a little, but the biggest thing you would notice is a long pause before the engine started accelerating after giving it the gas. This is because the TPS helps the car determine how much fuel it needs to inject into the cylinders. Without the TPS the car would need to rely only on the input from the MAF sensor, which would take a little bit of time to refresh.. The engine would still run but it would lag until the MAF sensor could accurately determine how much fuel the engine needs to inject. The TPS sensor gives instant feedback to the ECU as to what kind of airflow to expect, while the MAF sensor tells the ECU how much air the engine actually consumes. If you think this it the problem, unplug the TPS and start the engine. Twist the throttle cable and wait at least 2 seconds for the engine to accelerate. If it accelerates with no hesitation it's the TPS (But probably not). If it accelerates like it normally does, but a little delayed, then you're still looking for the problem. With the TPS unplugged, the engine might hesitate for 2 seconds or so before it starts to accelerate... This is normal, as the air fuel ratio will not be ideal (14.7:1). If the engine now throws a check engine light, simply plug the TPS back in, unhook the negative battery terminal, wait about 10-15 seconds, and plug the negative battery terminal back in.... BOOM no more CEL.

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Sorry yes it is a 2001. I hadn't considered clogged injectors. Could that cause intermittent cut-out? What's the best way to clean them? I thought driving with the O2 sensor out would eliminate the clogged cat possibility. It lets a fair amount of exhaust out and didn't make any difference in the problem.

 

Thanks for the good input.

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I've had a lot of luck with Gumout concentrated fuel injector cleaner and Gumout high mileage fuel injector cleaner. Or you could remove the fuel injectors and spray them with fuel injector cleaning spray, then leave them sitting in a bowl full of gasoline for a while. If that makes the problem get a little better, new (Rebuilt) injectors are about $50-70...
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Hi,

 

I have this exact same problem on my Legacy Brighton 99 with 2.2 motor.

 

Things I've changed recently:

- Oxygen sensors (both), plugs and wires, a year ago

- Knock sensor and fuel filter, last month

- Added a can of carbon cleaning additive 1500 kms ago

 

Info: My car burns some oil, ~250ml each 1000kms. Since the problem appeared, I'm pretty sure the car drinks more fuel, something like 15-20% more then before...

 

I will try the cleaning of MAP sensor, and give some news soon...!

 

Thanks for any other advices!

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