gshaffer

Out of nowhere my car is suddenly idling high around 1800 RPM (used to be 800) and it bounces between 1800 and 2200. I haven't done anything to it recently. The last work I did on the car was a hose job about 1.5 years ago. Any ideas?

gshaffer

Anybody? Sure could use some ideas!

Gamezilla

hows your vacuum?

MR_Rick

iTrader: (7)

yes check your vacuum lines. It sound like there is a vacuum leak.

aREX4X

sounds lke a hose blew off the manifold, check your lines on the back side of the manifold too!

x...

Chaosx1

I was wondering if that problem is like mine. When I start the car, it starts going between 2000 rpm and 3000 rpm until you touch the gas, then it goes to around 900.

BlueRex

Haha, that's just the AWS (accelerated warmup system). It's there to heat up the catalytic converters quicker. You can stop it by starting the car in gear.

ORX705

yeh sounds like a hose has popped off. check all hoses attached to the UIM and LIM

gshaffer

I got busy and walked away from this problem for awhile. Now my 2nd gen needs an alternator so I am driving the 3rd gen and the Idle problem is driving me f'ing nuts. All the vacuum lines look good, I replaced them with silicone less than a year ago. The wierd thing is that it bounces between 1500 and 2000 with the headlights off, but it bounces between 2500 and 3000 with the headlights on.

Anybody?

DaleClark

iTrader: (55)

Test for a vacuum leak. It doesn't have to be a hose per se - ANY air leak between the throttle body and the engine will cause this problem.

Also possible that you have a bad lower intake manifold gasket. '93s had a paper gasket that fails and blows out over time. Later cars have a metal gasket that's MUCH more reliable. Problem is it's a BITCH to change it out - pull turbos, you name it.

Also, make sure your throttle isn't stuck somehow. I've seen too-tight throttle cables whatnot that will cause all kind of funkiness.

Dale

gshaffer

Thanks DCF36. I don't think I have a vacuum leak, but I dread pulling the LIM to find out what the problem is. But that is what we do for our cars that we love. Anybody else have any ideas?

fd3streetkiller

I think your map hose blew off causing idle rough/bouncing.

Enconsiderate

i got the same, actually a lot of people has this problem. do a search for bouncing idle there is a lot.

what I have found its 1 of three things;

1. ecu problems, no real fix other than stand alone.
2. clutch problem. There is a switch that when you depress the clutch peddal it comes out. There was some guy on this forum that fixed this prob by replacing that switch. If you get in your car and look under the dash, when you depress the clutch you should see the switch/button come out.
3. Has something to do with your throtle body. if you remove your intake pipe going to the tb there is some sort of leakage you can see. I can't really help with this because i dont remember the full details of this fix. (i know big help huh) but i am hoping someone on here will know somewhat of what i am talking about and fully explain it.

if your wondering about my fix.... i dont have one yet. lol. I have been to lazy to concur this, but i dont see it too much of a prob. because after about 5-10 min of driving (when the car is FULLY warm) i notice that this goes away.

its a strange problem and i know it can drive you nuts!

good luck

ian

gshaffer

Thanks for the input. By the way, how do you "test" for a vacuum leak?

gshaffer

Again..........How do you check for a vaccuum leak?

RX7Wishing

whent hey are asking you about your vaccum... there asking how much vaccum your pulling... I hope you have a boost guage... anyway your boost guage should read anywhere between 15-19 lbs of vaccum at idle.

[SLO NIZ]

Hey sounds like my prob, my bounces from 1000 to 1500 but i got no vaccum leak at all but it did start doing it straight away after i plugged my new pfc in.

Speed of light

iTrader: (8)

Yea-- I had a similar problem about 5 years ago. Car started idling fast, then faster and usually wouldn't come back down. Problem turned out to be related to the fast idle actuator (on the back of the throttle body). This is a thermostatic (wax pellet) device that uses hot engine water to release the fast idle speed cam. Mine clogged with crud from the cooling system that prevented water circulation and thus never warm up. You can check to see if the throttle is still on the fast idle cam when you're experiencing this difficulty.

It's actually easy to service; if I remember correctly, you'll have to disconnect a coolant hose and remove three or so screws to get the unit off. I cleaned mine out, put it back on and problem solved.


Hope this helps.