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hyte
12-13-2005, 11:15 PM
i have a 98 legacy gt limited and am experience a hesitation when i press the gas under cold conditions and sometimes under hot conditions. like the car is sputtering or struggling for power but then it picks up. this problem is mostly when the car is cold (mornings when i first start it). the other day i had a IAC code pop up for the entire day but the nex morning engine light was offf.
can anyone shed some light on this problem.
thanx

hyte

Huffer
12-14-2005, 10:21 AM
Try cleaning the IACV.
when did you last change the fuel filter?
Are you due for an oil change?
How old are your plugs/wires?

hyte
12-14-2005, 12:07 PM
The plugs were jsut change to platinums about a month ago, i havent changed the fuel filter as yet, and where is the iacv and how do i go about cleanin it,
thanx for the quick response

Huffer
12-14-2005, 12:57 PM
Might also want to check the condition of the MAF sensor.

IAC valve usually found connected to throttle body.
Might want to try running some Chevron Concentrate fuel/injector cleaner...

BAC5.2
12-14-2005, 06:05 PM
The plugs were jsut change to platinums about a month ago, i havent changed the fuel filter as yet, and where is the iacv and how do i go about cleanin it,
thanx for the quick response

Pull the plugs out and replace them with plugs that are good.

Platinum plugs last so long, because they don't provide a hot spark. You could actually be misfiring because of insufficient spark.

NGK Copper plugs are cheap, and reliable. I think they are under 3 bucks each.

A fouled plug will cause poor running.

You've got the EJ25, right?

Huffer
12-14-2005, 09:41 PM
first post says 98 gt limited, so I think you're onto a winner there BACS.

BAC5.2
12-15-2005, 12:18 AM
Wow, my deductive skills are incredible aren't they?

Any other MIL codes? Knock Sensor codes perhaps?

There was a TSB in 98 for EJ25 Engine Hesitation because of knock sensor malfucntion causing the ECU to memorize retarded timing between 1500 and 2500 RPM. But it throws a Knock Sensor #1 Malfunction code. Subaru says you need to replace you ECU for that problem, but RS25 guys say replacing the knock sensor fixes it.

Legacy4Life
12-15-2005, 09:28 AM
I had the same problem last year when the cold weather hit.

Found out it was my fuel filter. It was so blocked the mechanic couldn't even blow throw it. Come to find out they ought to be changed every 40,000 kms or so for optimum performance. I haven't had the hesitation since then. Keep in mind the car wants more fuel when it's cold and that's when it will act up the most.

By the way, if it is blocked and you change it, you'll likely have to change it again soon (I'm talking from experience here) because the new one will pick up all the crude that couldn't make it to the old one since it was full and it will block up sooner. After that you're fine. It's not an expensive part and easy to change!

hyte
12-15-2005, 03:16 PM
thanx for all the good information. maybe i will just go to subaru and pick up the plugs from there. as for the fuel filter yeah i will probably need to change it. there are no other codes just the iac one which cleared itself

thanx for all the help
hyte

BAC5.2
12-15-2005, 09:12 PM
Good luck at Subaru. They will probably try to charge you $10 bucks a plug.

Pepboys. NGK Copper's. Just a few bucks each. When I swapped them in, I noticed an almost immediate improvement in every aspect of driving. I replace my plugs every 15k out of habit. It's easy, and cheap. Every 4th or 5th oil change just do plugs too :)

subieyacht
12-29-2005, 02:22 AM
Wow, my deductive skills are incredible aren't they?

Any other MIL codes? Knock Sensor codes perhaps?

There was a TSB in 98 for EJ25 Engine Hesitation because of knock sensor malfucntion causing the ECU to memorize retarded timing between 1500 and 2500 RPM. But it throws a Knock Sensor #1 Malfunction code. Subaru says you need to replace you ECU for that problem, but RS25 guys say replacing the knock sensor fixes it. i think im having this problem, cuz i pulled a knock malfucntion code the other day and im having this same hesitation problem. i'll ask at subaru tommorw.

shazapple
12-29-2005, 01:12 PM
Im having a similar problem too. Im going to try running some gasline deicer through, then Ill move onto the fuel filter. Its beel at least 40k km since its been replaced

Legacy4Life
12-29-2005, 04:27 PM
On thing about Subaru's is that they never really have been a very good "cold" running vehicle. They really do like to idle a while before they get driven when the weather is colder.

Sarra
12-29-2005, 11:23 PM
I'm not sure about that... They do idle high when cold, but so does our toyota truck. then again, our Outback had tons of trouble starting in cold weather and my car simply starts after 1 full revolution of the crank pretty much... That's more to do with the battery and starter though.

Wiscon_Mark
12-29-2005, 11:30 PM
gas line antifreeze does wonders in cold weather

noza
12-30-2005, 06:21 AM
also check the egr valve to make sure it is free of crud. it's the thing that looks like a blow off valve.