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Idle Surge, very bad, need help!!!

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xhypno

20+ Year Contributor
186
1
May 12, 2002
Pembroke Pines, Miami_Fl
Ok here is the problem. On May 6, I bought a 1994 ES Talon with the 2.0l 4g63 motor. It has 65k on it, and is in very good condition. About one week ago, the check engine light went on, and when at an idle the rpms jump about 300-700, and when the clutch is in or when not in gear (slowing down) the same surge appears.
I connected an ohm meter to the data port and came up with a code 43. Which is for the egr system. I tested the thermo valve sensors, all working. I test the vacum to it, good. I figured all that is left is the egr valve. I removed the valve, and it was fauled bad, alot of carbon deposits. I used carb cleaner and a wire brush to clean it. I then vacum checked the valve. It seemed to be working.
At this point I thought every thing should be fine. I put the valve back in and started the car. It was fine. But after a 10 min drive later that day, it started again, but this time with no check engine light.
I have checked every sensor under the hood twice with the ohm meter and still can't find another problem.

Does anyone have a suggestion?????

Any help will be appreciated!!!!! Thank you Philip
 
My car has an idle surge issue as well. My car cranks fine cold, it idles around 1000, where it was set, then when it is warmed up and has been driven down the road, it will idle anywhere between 1400-1800rpm. i also noticed if i turn it off when it's warm and try to crank it back up, it will stall for several moments and either die or keep stalling until you give it enough gas to get it back into the 1400-1800rpm range. it's been doing this for months now and with current funds i've just put up with it, but now it is time to get it figured out and fixed. oh and if it makes any difference, CEL is on at all times. any advice is appreciated, thanks.
 
Ok I just bought a 1992 Talon TSi AWD automatic with 105k miles on it. The only problem is idle surge when it is in park or neutral.

When it is in Drive or Reverse, no problem, the idle is a little high at 1000, but that can be adjusted by screwing in the idle adjustment screw. However, when the car is in park or neutral, the car idles over 1000 and surges up and down between 1000 and 2500 like I am tapping the gas pedal. Once you turn the A/C on, the problem goes away and the idle goes down to the normal 1000.

The only mod on the engine is a manual boost controller.

I have the same idles surge issue....turning the AC on brings it to a normal steady idle. Has anybody else had this issue with this specific symptom?? BTW I am completely stock.
 
Make sure both EGR gaskets, one to the head and one to the intake, are good and dont have a leak. Mine had to be replaced and had leaks and caused my rpms to run high. The one to the intake isnt manufactured anymore so may be kind of difficult to find.
 
You think that's bad. after drving aroung for a while my idle will start fine but eventually it will idle at 1900rpm and stay that way unless I leave the car off overnight. Try stopping at every light and your car idling at 2k. not fun when I stop somewhere and get back in the car I can't even put it in reverse the idle is so high so I have to start the car in reverse. :cry:

I have this exact same problem... It only idles high after it has been warmed up!

Edit: After reading the whole thread it looks like I'll be checking the ISC and hoping I didn't burn $100+ on a new TPS I didn't need...
 
Me too. I got my car out 2 days ago, for the first time since last August. When I start it, I have to feather the throttle for probably less than a minute. Then it runs at about 1000 RPMs for a minute, then the idle slowly creeps to about 2100. Once it gets there, it starts bouncing between 900 and 2100 very quickly. If I turn the a/c on, it stops immediately. It only does this when the clutch is engaged or in neutral. This was never a problem before I parked it. I really dont know where to start. Any suggestions would be greatly appreciated. I havent filled in all my profile yet, but it is pretty heavily modified and only has 67,00 miles on it. Does anyone know if running a can of c foam through it would help at all since its been sitting so long, or no? Oh yeah, its doing this well before its at operating temperature and doesnt stop once its warmed up either. Other than that, its running like a champ.
 
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Ive had a few people tell me, its probably the idle air control valve. Now i have a question. It may be the stupidest question ever, but here goes. Do idle air control valves come in different sizes to where they can be upgraded to handle a higher horsepower engine or are they all the same for the same car? My bad if I sound like an idiot, but im fairly new to the DSM game and im trying to learn everything I can about them.
 
have you adjusted your BIS screw an seen if the O-ring behind the screw is good or even if you possible lost the biss screw!?
 
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