help with hesitation

[strat81]

got to drive the 95 legacy we picked up for the first time today and it's having some running issues.

car is a 95 L, 2.2, 5spd with around 200k on the clock.

when the car is cold, it starts up and idles fine. as it comes up to temp, it gets a little finnicky as the idle will jump around and sometimes just stall out. it will start back up with a bit of throttle and most of the time settle back into a normal idle.

driving once up to temp is tricky as the car will buck at times and attempt to stall when coming to a stop.

recently replaced were plugs (ngk's), plug wires, and radiator (it's not overheating and this probably has nothing to do with the problem but i figured i'd mention it.)

I'm trying to avoid the guessing game of replacing a bunch of parts in hopes that i get the right one to fix the problem. i'm thinking it could possibly be one of many things... crank sensor, cam sensor, fuel pressure regulator, fuel filter, throttle postion sensor, maf sensor, pcv valve... i'm thinking something sensor related as if memory serves me correct, the car runs on a set table of parameters until it reaches a certain temp and starts pulling data from the sensors.

any thoughts?

[Okin DaVanh]

No CEL? Have it scanned anyways, to see where your readings are at. It's free anyways.

---I'd also go back and double check the parts the previous owner installed. Did you check the intake? Sometimes, if left loose or with a gap somewhere, it could give you the same symptoms. MAF would be my "opinion", as it changes airflow as the car warms up as well.

[strat81]

no CEL...

I really don't want to take it to get scanned as it's running THAT rough that I'm not sure I would make it to the store to get it scanned and the be able to get back from the store. I had a hard enough time taking it around the block last night.

I'll check the intake tract for loose connections but I'm pretty sure that the previous owner didn't really touch it. (it's my gf's brother's old car and he is less than mechanically inclined)

[Huffer]

Take the intake off and see how dirty the MAF is, even the intake hose.

When the car is warmed up the car is now in regular mode, so normal fueling, air + spark are taking place. If any one of those are bad then the car will stall due to lack of fuel or lack of air (or too much).

My other suggestion is a front O2 sensor...

[strat81]

cleaned the maf and changed out the pcv. she runs great...

now we just need to deal with the overheating... pretty sure we'll be doing headgasket. :smt021

[J-Rock!]

cleaned the maf and changed out the pcv. she runs great...

now we just need to deal with the overheating... pretty sure we'll be doing headgasket. :smt021

not many 2.2's need headgaskets,, but it does happen,, I would start with thermostat, and make sure your water pump is fine,, cuase people forget about the ol waterpump,, they do go bad, alot more than headgaskets blow

[strat81]

replaced the thermostat when i replaced the radiator. we've also double bled the cooling system.

i know the previous owner (my gf's brother) does horribly with cars and he was having overheating problems. i would not put it past him to have driven it to the point where the heads are warped.

[impreza_GC8]

2.2's are not known for head gasket issues. Hopefully that is not the case for you. Thanks for the tip about the dirty MAF, I picked up the cleaner stuff the other day. I've got some hesitation as well, we'll see if I can't fix it.

[birukun]

Idle Air Control Valve dirty?

I can't say for sure, I just know it is either open or closed after warm up.

Bill in SD

[Huffer]

cleaned the maf and changed out the pcv. she runs great...