Idle Issues and Common Fixes

[M.Hicks]

Fluctuating, erratic, inconsistent, poor, or no idle.

Step 1. Check for vacuum leaks - There are a few methods for finding or determining if you have a vacuum leak. The first is a audible/visual inspection. Look around the engine bay for unplugged, cracked, or faulty vacuum lines. Large vacuum leaks will "hiss" so you may be able to hear them. Another method for locating a vacuum leak is using starting fluid(some like to use soap and water in a spray bottle). Spray a small amount of starting fluid around possible vacuum leaks(vacuum lines, gaskets, etc), if there is a leak, the starting fluid will makes it's way inside the engine and the idle will 'jump' This is a sure sign of a vacuum leak. Soap and water in a spray bottle will shows signs of a vacuum leak by making small bubbles near the leaking area. If you find a vacuum leak, replace the faulty part.

Step 2. Clean the Idle Air Control(IAC) and the Mass Air Flow Sensor(MAF) - Here are links to the cleaning procedure:
IAC
MAF1
MAF2

Step 3. Set the Timing, Idle and Throttle Position Sensor(TPS) - Here is a link to the procedure for the 2.5L, the process should be similar for the 2.0L:
The proper/accurate way to set timing, idle, tps


This thread is open, so post feedback below.

[neilh2o]

other possible causes for poor idle: low compression on one or more cylinders (burned exhaust valve etc.), defective or sticking pressure relief valve in the oil pump (93-5/96 manufacture date. there is a simple procedure listed in the 2.0 archives to isolate the problem to the pump or the valve lifters themselves. what happens is a valve(s) either doesnt fully open or close causing a rough idle), collapsed lifter (with lifter removed from engine if you can depress the internal piston with your fingers the lifter check valve is clogged)

[neilh2o]

There is another way of cleaning the iac valve that hasnt been discussed. This procedure is for 93-95 2.0 probes.

Remove the 4 bolts holding the iac valve onto the throttle body.
Turn the valve upside down and youll see 3 cavities.(There are four cavity holes but only three actual cavities.)
What you want to do is; pour Seafoam (cleaner that removes carbon) into the cavity directly below the electrical solenoid.
Fill the cavity and completely cover the plunger (you can see the tip of the plunger inside of the cavity).
Look closely as you want to make absolutely certain that you pour the solution into the right cavity).
Leave the solution soak for 15 minutes.
Then, dump out the solution being careful not to get the fluid into the other cavities.
Apply compressed air for 20 seconds into both sides of the cavity to blow out the carbon deposits.
Again, fill the cavity with seafoam but this time do not let it soak. Dump the solution and re-apply compressed air and make sure all the carbon and seafoam are removed.
Connect the IAC valve to the engine harness making sure the key is off.
Hold the IAC valve and watch the plunger while an assistant turns the key to the 'on' position.
Do not crank the engine as coolant leakage will occur.
The plunger should move open and close quickly.
If the plunger does not move; the procedure must be repeated. (Remember to disconnect the IAC valve from the harness.)
If the plunger opened and closed normally; disconnect the IAC plug from the harness, then pour water into the solenoid cavity.
Dump the water out.
Do this 2 or 3 times.
Apply compressed air for 20 seconds until the cavity is dry.

[J_Noftsier]

there is also different kinds of sure fix fluids to use to clean your engine weekly that should be done. I always run offroad octane booster. Even if your not supposed in a street car. ( really is worth the extra 2 bucks though . And a higher octane gas and of course the fuel line cleaner fluid etc. to put in your car weekly

[Raydar]

Let's say the egr is at fault. What egr would fit a 96 2.0? I'm looking for one for my engine and I have no luck. Are there other year models that will fit my engine? Will an egr from the 626 fit? If so what year?

[back2probin]

POST IAC Cleaning issues!!

I cleaned my IAC per the directions posted in this thread. Prior to this I only had a low idle at a stop 'in gear'. After cleaing it, my idle in park is in a constant jumping loop idle, where it will go from 2000 down to 1200 and back again. In gear it will idle at 1200.

I should have left it alone, because it was tolerable before, but now after I cleaned the IAC its HORRIBLE!!!!

Any help would be GREATLY appreciated!!

[arneeche]

did you remember to burp your coolant system after you reconnected everything

[74eldo]

Let's say the egr is at fault.

94 PSE AT
Yea, I am getting a 28 code, EGR system fault. Cleaned my EGR modulator valve and EGR control valve, checked vaccum for leaks, and still getting eratic idle. Have not seen much on the forum about EGR systems, anyone have any experieance with this issue??


http://www.performanceprobe.com/inde...ticle=94-18-04

[back2probin]

did you remember to burp your coolant system after you reconnected everything

Not sure how to do that. Any ideas or at least the thread that tells you how to do it?

[arneeche]

basically, take the caps off of the coilant fill locations and start your car, fill it up to the proper level while its running and then go over the lines squeezing or shaking them to get the air bubbles out of the lines so that you don't get them going up into your IAC. just burb and refill, maybe rev it a few times to see if it gets any lower.

[back2probin]

Well, tried the burping to no avail. Of course it only took about 20 seconds for coolant to start spilling over the main fill cap. It appeared to be chocked full of coolant. I unplugged the IAC and it made no difference. That tells me if I hadn't cleaned it in the first place, I would NOt have to be buying a new one now. Thoughts?

[96fazda]

i got the tb bypass done i idle at 625 unless i cruise for a while and when i stop i idle at 1200 then after about 30 seconds it drops to 675 700 why??? i have no check engine light (anymore) no vac leaks or bad gasket

[Z3CHYD]

I have a 94 2.0 Probe. I'll start it and it'll idle at about 1200, and drop down to 800 or so. But after it warms up, when I come to a stop and put my foot on the clutch, it'll either fall down to 100 and shudder, but stay running, or will just plain shut off, it goes back and forth. I can start it an keep tapping the gas to keep it running, and it drives fine, does this sound like the iac to anyone? anyone else have this problem?

[itsasmallboat]

I have a 94 2.0 Probe. I'll start it and it'll idle at about 1200, and drop down to 800 or so. But after it warms up, when I come to a stop and put my foot on the clutch, it'll either fall down to 100 and shudder, but stay running, or will just plain shut off, it goes back and forth. I can start it an keep tapping the gas to keep it running, and it drives fine, does this sound like the iac to anyone? anyone else have this problem?

That is crazy because I am having the exact same issue. I've cleaned the MAF and IACV, burped coolant, and still the exact same issue.

CEL is throwing O2 censor, so I think what's happening is the oxygen readings are way off and the car is dumping too much gas at times and not giving enough at other times.

Just my two cents.

-brandon

[Amopower]

You may wish to replace that IAC link with this, since that Adamk site seems to have been down for a while now:
http://www.mx6db.co.uk/?loc=4&id=6&view=guide
This one seems to be a close clone of that site anyway, but i think it has better IAC component pictures than Adam's had.