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View Full Version : hard acceleration fixes idle problem...weird



amx
08-10-2007, 10:06 PM
My celica runs fine when the engine is cold or while driving, but as soon as it reaches operating temp, it starts idling really rough and rpm drops to 400 and lower. It stalls when I clutch in and come to a stop, to the point that the car wouldn't stay running unless I kept my foot on the gas. This had been going on for about the past week.

So 2 days ago it was idling low again like it was getting ready to stall, and there was a line of stopped traffic ahead so I turned off onto a side road and punched the gas, shifted at about 4500 rpm, up through 4th. Come to a stoplight and wtf, the idle's fixed itself. Right around 8/850 like it's supposed to be, and hasn't stalled since.

I'm going to pull the throttle body off and give everything a good cleaning this weekend. I read that among other things, a bad coolant temp sensor or EGR valve sticking open can cause the stalling. So what would make the idle go back to normal like that?

85gtsblackman
08-10-2007, 10:40 PM
suggest seafoam for the engine and b-12 in the tank

Blackcloud
08-11-2007, 06:30 AM
850 is pretty high for idle aint it?

angryyoungnpoor
08-11-2007, 07:39 AM
850 is about right. My swap idled at about 1k and that seemed normal for an open exhaust. It's no diesel engine.

have you tried checking your timing?

amx
08-11-2007, 08:51 AM
Yeah, service manual says 800 +/- 50 for the 4afe. For what it's worth, that's where my engine seems to run smoothest anyway.

I have not checked my timing yet. I'll put that on the list of things to look at if cleaning + seafoam doesn't solve the idling issue. I'm just really stumped about why romping on the accelerator seems to have helped so much. Maybe I just have a lot of crap in there gumming things up and it needs to be blown out? No idea.

85gtsblackman
08-11-2007, 01:05 PM
clogged cat will idle high to, just gut it

MarcusM2007
08-12-2007, 06:29 AM
odly enough one day my car was idling really high, at like 2500, and it would coast pretty fast without me touching the gas. It got up to 30mph without me touching the pedal. Then I floored it, engine sounded like it threw up and then it was all fixed lol. Must of ate a bad civic lol

celicaGT90_05
08-12-2007, 07:44 AM
hell I wish my truck idled at 850 lol its more like 900-1000, and about 1800 when warming up

85gtsblackman
08-12-2007, 12:18 PM
my idle up thingy is broken so my car idles around 700-900 rpm constantly, i just drive really old man like till it warms up a lil, or hold it at 2k till i leave my driveway

dad cranks it up on the other hand and revs the crap out of it causing backfiring and me yelling "damn it no its not carbed" like my truck is

amx
08-13-2007, 01:29 AM
lol @ ^

Update: I cleaned the throttle body, which did have a decent amount of carbon buildup in it, then split a can of seafoam (nearly pissed myself when the smoke started appearing) between the engine and gas tank.

A few things I noticed right away:
-The idle seems to have smoothed out a lot. There was a little bit of a dip in rpm initially when I clutched in to come to a stop, but it went away as I drove. It's also definitely idling higher now (like around 900 or so), but it feels much steadier. The tach needle used to bounce around a lot but doesn't do it at all anymore.
-Engine has become quieter. I had a really annoying rattle at about 3000 rpm that is virtually gone now.
-Can't say whether performance has improved (it is an ST, after all--plus I drove my mom's Supra all weekend so everything seems slow now :hehe: ), though the response does feel better.

I'm gonna hold off final judgment until I've driven it normally again, the caveat being that driving it hard has fixed the issues in the past, and I did romp on it pretty good after doing the seafoam. But there has been a noticeable amount of improvement, so I think I'm going to sit back and see what happens now. :D