6G Celicas Forums

Probably 30ish a day, 6 days a week. Only getting about 18-20 mpg from it, which sucks a little haha.

Long story short, my 5s has a pretty rough idle when not in park. Got the car with no grommet in the pcv valve. After replacing the pcv valve and grommet, the car had a significant loss of power, and the idle was rough and low. So low that it would bounce around and eventually stall if I came to a full stop for too long. Reinstalling the original PCV/grommetless setup didnt help, so the car was towed to the mechanic, where they managed to get it to drive a little better, but couldnt solve the problem entirely. Ran some seafoam through it, and I got a lot more power out of the car, but the car would still idle rough and eventually stall(although it was significantly better than previously.) Last thing that I did was adjust the idle speed screw, and that seems to have acted as a bandaid for this problem, but I've read that this solution may not be permanent. No stalls since this, but the idle still gets rough. Heres a little list of whats going on.

The Bad
-CEL, showing p300-304(random/all misfire), P171(System too lean)
-Idle bounces ~700-400 RPM
-Loss of power
-When battery is disconnected, ECU seems to have a steep learning curve if you will, as it takes several days of driving before the car starts to drive somewhat normally again. Could be due to the lean fuel/air
-While at the mechanic, we ran some fog through the intake and saw that the EGR was leaking pretty bad.

The Good-ish
-Compression tests done at shop, cylinders okay.
-Seems to idle better when cold.
-The rough idle can be "fixed" about 70% of the time by turning on the AC. This makes me think the problem is air/vacuum related, and not fuel related.
-The rough idle also tends to go away once I get the car on the highway, or if I get it around the 4-5k rpm mark. Like the AC, this doesnt always work.

At this point I have ordered a new EGR and vacuum modulator, and am waiting on their arrival. If that doesnt solve the problem, I was thinking about replacing the injectors and fuel pump, as the seafoam did seem to help a little and the ones in my car are older and could use replacement anyway. Besides that I'm not sure how to tackle this issue. Any help would be appreciated.

A bit of an introduction.
Growing up in NYC, we didnt have a car, because we didnt really need one. I've always had a strong appreciation for cars, and 4 months ago I got my first. Its a Red 1998 Celica GT hatch.

The bad:
She came with 2 pretty worn motor mounts, a trunk that wouldnt open, an intake hose held together with tape, as well as several other minor problems. It has ~235k miles on it. Last oil change was done yearly(if that).

The good:
Pretty much everything else. Just had timing belt and a few other parts changed <10k miles ago. Drives like a champ, no rough idle, starts right up even in sub zero temps. Trans fluid ok. As for the high miles, I am 3rd owner, and have been dating the 2nd owner since she got it fron her uncle, the first owner. Needless to say, I have a good knowledge of the history of the car. Majority of the miles came from first owner (who maintained it well), an older gent who was dating a girl in Jersey while living in Connecticut, so mostly highway

I love the car. Since I've gotten it, Ive fixed the trunk, done brakes and an oil change, swapped broken intake with SRI, and currently have the motor mounts on their way. Still have a couple very minor things to fix, but nothing else major. My only worry is the mileage. I would love to do some real performance mods, but the car is old, and I'm slightly worried that things might go south if I push her too hard. I guess I'm wondering what the community thinks would be the best direction to go with her. Do I take the old lady and give her the time of her life at risk of her health, or do I just focus on keeping her alive?
Also, been lurking these forums since before I got the car. Both the information here and the community involved are incredible, so thanks for that

Hey, I'm looking for the OEM air intake hose as well as all motor mounts. Interested in price plus shipping to 11367.