new 02 wrx owner having troubles

[nward61988]

Just bought an 02 WRX 4EAT about a month ago and I'm having some problems. The biggest one I need help with is when I'm driving at low speeds and rpms I won't move my foot from the gas and all of a sudden I will lose power. Then out of nowhere it will find power again. Hasn't happened yet when getting on the gas just at lower rpms. Any suggestions on what it could be? Also it has been having a rough and fluctuating idle as well. I don't know much about WRXs yet always wanted one now I finally got one, and I want it running right before I would do any mods. So any help is greatly appreciated.

Here's the info on the car if needed
2002 4eat Automatic Tranny 82k miles
Full 3" DC Sport exhaust
Aftermarket BOV

[EJ257]

Is the car tuned?

Can you datalog?

Has the BOV been properly adjusted?

[zax]

Is the exhaust a turbo-back exhaust? If so, who did the tune?

Also, IIRC, many BOVs have significant issues on the 4EAT:
4EAT Basic Information FAQ

Using a Blow-Off Valve on a 4EAT

Yes, it can be done, but the difference between using a BOV on a 4EAT is that you will not hear the “pssshhh” sound when the transmission shifts. This is because the 4EAT holds it’s boost during shifts. Verdugo, our resident moderator, has tried out many aftermarket BOVs and determined that only one worked correctly: The HKS.

APS- Smoothest of the bunch, but could not be heard at all.
Blitz- Would not function properly
Greddy- Would not function properly
TurboXS- Would not function properly
HKS- Best BOV, works fine at all boost levels

[nward61988]

The exhaust is a catback I believe, no the car is not tuned nor do I think it ever has been. And it loses the power not in boost as well. I was thinking maybe bad spark plugs, or maybe needing a complete tune up? it feels like the power just cuts out completely, then catches again out of nowhere. Thanks for the help, loving my first WRX so far.

[EJ257]

The exhaust is a catback I believe, no the car is not tuned nor do I think it ever has been. And it loses the power not in boost as well. I was thinking maybe bad spark plugs, or maybe needing a complete tune up? it feels like the power just cuts out completely, then catches again out of nowhere. Thanks for the help, loving my first WRX so far.

Again...

Can you datalog (which will tell us what's going on with the car)?

Has the BOV been properly adjusted?

[nward61988]

No I cannot datalog never done it before, and I'm not sure about the BOV being adjusted, the guy I bought the car from basically never drove it or was into it so he didn't inform me on to much.

[frenziedcage]

You could be experiencing a misfire I had the same problem with my 02 wrx. It had a rough idle like you're explaining. Same thing with losing power at lower rpms. I scanned my car with obd2 scanner and it had a misfire at 700rpm. It could be a timing, fuel, ignition problem etc..

Do you have a turbo back exhaust? Is the car tuned?

[frenziedcage]

In my case my timing was off. Have you had any CEL come on?

[nward61988]

no the car is not tuned, and I was told full 3" exhaust I'm assuming its a turboback? No CEL lights have came on to this point. How much are those scanners and where to get one? Also where should I start looking? I just did a fresh oil change using 5w-30 full synthetic valvoline synpower and also added Lucas injector cleaner and it actually seems like its worse now. When you say timing do you mean timing belt?

[frenziedcage]

Yeah the timing belt, you might need to adjust the pulleys on the belt. Which takes about 1-3 hours depending on what tools you have. It took me about an hour and half. If you pop your hood and look at the teeth where the belt meets the pulley there should be a marking point somewhere indicating where it should be adjusted. Mine was on the front of the pulley. Just look for a marking that meets up with the other marking. You'll know what I'm talking about when you see it. In my case it looked like it was marked with a fluorescent green / orange color. Anyways the markings should meet up. You can buy the obd2 sensors at harbor freight and also pepboys sell them too I think.. If you were to do this yourself it would be the perfect opportunity to replace your timing belt, since you pretty much gotta take the whole belt off to readjust the pulleys.

[frenziedcage]

Turboback exhaust is downpipe + catback

[nward61988]

Ok as for the timing I was planning on doing my 90k maintenance and do the timing belt and water pump at the same time. What is the best timing belt to use? I heard gates makes a good performance one. For the 90k what all needs to be done, I've looked at a couple places and its always different. Then in terms of upgrades i got a couple ?s. Do I need an accessport if I was going to get a pro tune? So far I'm thinking high stall torque converter, accessport, up pipe, downpipe, full exhaust, new plugs as well. Got any more suggestions for me on which way to go? Also what brands do REX owners recommend with reasonable prices, and the best site to get parts from. I will be starting to collect my parts now so any info would help, thanks.

[nward61988]

I have heard mixed reactions about getting headers, as well as getting a CAI or short ram. People seem to think its a waste of money?

[zax]

I have heard mixed reactions about getting headers, as well as getting a CAI or short ram. People seem to think its a waste of money?

At your current level of mods, header and CAI would not be effective mods. In fact, if you were to get a larger diameter header, you would be sacrificing turbo spool due to decreased exhaust gas velocity. Right now your largest breathing restriction is after your turbo: the downpipe.