I have a weird problem with my '99 se's (5 speed) idle. The car a little over 122k miles. The engine is stock.

The car starts fine, runs great but when I approach a light or stop sign and push in the clutch and brake the rpm's drop and the car almost stalls. Sometime it does stall but not often. It seems as though the engine or ecu catches the engine rpm's just in time before it stalls. Aftewr they drop to 300 or so then they come back up to about 650.

This really bothers me. It doesn't matter if it's cold or hot outside. Happens all the time, esp when the engine is warming up. Can anyone give any ideas to why this is doing it?

I keep up on all maintance of the car. Changed the necessary parts.

Any help would be great!!!

Thanks,
tom

 

Clean your throttle body and the IACV.

 

Yep that's right, Throttlebody, use the same TB cleaner to clean out the IACV, the IACV is #11 on the pic below:



Problem solved!

 

Is there a way to SeaFoam the iacv?
Jae

 

had exact same problem, it was the maf

 

Still helps to clean TB and IACV once in a while

 

thanks for the info. i cleaned the throttle and IACV a long time ago. i guess the build up cam eback. I give it a try again. Thanks! Let you know how it goes.

 

Maybe this is a problem with Deep Evergreen 5 speeds...?

I have that EXACT same problem, and sometimes really makes me hate my car. I have done ALL of the preventative maintanence (air/fuel filter, PCV valve, cleaned TB/IACV, replaced IACV, oil/filter, seafoamed through Brake Booster, Knock Sensor, Sparks w/ NGK Coppers). Right now however, it seems that I have a leak around my intake mani that might cause this problem. I will hopefully have it fixed in the summer time, unless I have time around breaks from college.

Try hooking a vacuum guage up to see if your vacuum is where it should be (I still haven't done this).

 

My '95 SE 5 speed has this problem as well. Tonight I think it made my check engine light go on, since I was trying to shift extra smoothly to not upset a sick passenger (mother-in-law's blood pressure), so I was running much lower RPMs than usual before shifting.

Can someone answer for me whether the CEL would go on from the RPMs dropping immediately after a downshift and simultaneous braking? I also had more power-drawing stuff turned on at the time, due to driving in cold damp weather (rear defrost, defrost, and radio). Could it be my alternator?

I don't want to take the car to the dealer or my mechanic if I can just check the codes and reset them myself (which I've never done before but I think I am going to try if it isn't too damn cold tomorrow!).

Thanks for any help!!

Also, what is an "maf"?

 

Mass Air Flow Sensor, it is the black "tube" that is directly behind your intake box, closer to the throttle body. It measures the amount of air is getting introduced to the engine so that the ecu can adjust how much fuel to give.

Best thing to do is check the codes, and post what you got in here. I'd like to see if there's a correlation.

 

When was the fuel filter last changed?

Dave

 

I thought of another variable as to what may have caused the CEL to go on, and it may be related to filling up yesterday with 92 octane gas instead of my usual 93 (92 was the highest they had). I just read in my Haynes manual that the CEL can go off on its own after a couple consecutive drive cycles without any issues, so I'm wondering if I put some octane booster in the tank, maybe that will cause it to run cleaner and the CEL will go off. Any thoughts?

Still, if it isn't too cold, I am going to check the code tomorrow or the day after.

Thanks for your responses, guys!

 

Ahh, you're way of base if you think 92 as opposed to 93 octane can cause this problem.

 

To elaborate on that:
1) the knock sensor is the one thing I can think of that would post a code if too low of an octane is used.
2) the knock sensor should not be set off by 92 octane (in fact, in Cali 91 is the 'premium')
3) the knock sensor will post a code, but will never light the CEL.

I suggest you pull the code and find out precisely what the ECU sees is wrong.

Dave

 

After doing all that preventative maintenence on my car, I've narrowed my problem down to:
1) My slight intake mani leak, most likely from the gasket between the LIM and UIM.
2) A bad batter, or alternator.

I would much rather have this be a gasket problem. I can't wiat to get this fixed, it sucks driving with this.

Oh yea, the only other thing I can think of is that I didn't replace the gasket between the IACV when I cleaned/replaced mine. I don't think that's the problem, or the majority of the problem, but that's something else to keep in mind.

 

It sucks to have this problem but it is a good thing to know other's have noticed something similar. Thanks for all the input. I haven't had the chance yet to clean the throttle body or the IACV but I hope to this weekend. I changed the fuel filter less than a month ago at about 122k. It wasn't very dirty at all. I always run 93 through the car and try not to let the tank run too low before filling up. My gas milage has ranged from 24-27 depending on driving condition. I'm thinking it's the MAF but I rather not have to take the car apart again. I used to have CAI on a while back but the problem started way after I had removed the CAI. My plugs are new and I have a clean K&N air filter in there. i'm wondering if maybe the oil used on the K&N may put a coating on the air sensor in the MAF? Could this be cleaned too? I'm thinking somehow the sensor (resistor looking piece) may be causing the problems.

What does everyone think about that? Just trying to think outside the box. Work would be proud...

 

I had a similar problem.

When I saw MAXRB8's picture a few nights ago I went and cleaned my throttle body.

When I did this I took my whole intake assembly out and set it aside. When I cleaned the throttle body it was NASTY, I actually plan on going in again after a few thousand miles to really clean as deep as I can. I took alot of time and A LOT of shop towels doing this and if came out pretty good.

When I was getting the intake assembly ready (clean) to put back in the car, I noticed that the tube that went from the intake to the IACV didn't seem to have a very tight seal. There was also a small line that screws into the mid-pipe (for me, for stock it may just clip into the resonator) and I re-attatched that as well.

I did not clean the IACV because I took so long with everything else but I took it for a test drive anyway. From the 1st test drive (2-3 days ago) to now the car has not dipped below 650. I have cruised in my neighborhood just at idle and pressed brake/clutch simultaneously (which used to cause it sometimes) many times and I have revved the car very hard MANY times (used to dip below 650 and right back up after hard revving) and it has not dropped below. I have used Heater/Bose/lights in all combinations and it seems as if for now the problem is gone.

 

That's interesting. Maybe if I can find time, I can do this. Did you have any problems taking arart the intake. What was involved and anything to look out for? I've never gone that far into the engine but would like to tackle it.

Thanks!