Hey guys, I'm Mars and I have a 2000 MaxI'ma SE 5sp. It has 198K miles on it. When I bought it the car had a rough idle, but it would never stall. Recently the car has started to stall when I push the clutch in. The worst case was today, I was backing up and the car die 3-4 times before I was out of the spot.
Thanks for the help!!

 

My guess is iacv. Can you describe the rough idle you were having?

 

The RPM's would dip below 1500 and the car would shake as if it was about to die, but it would never actually die until recently. It was like it was shuttering. Normally the RPM's would jump back up normally but now the car is dying.

 

Honestly sounds a lot like my iacv before it died. On startup rpm would drop to near stall and then surge up/down a while until the car warmed up until one day it stopped working and stalled. Common problem and youre at that age/mileage. Search iacv and p0505 on here, if you replace the part go OEM only and be sure to pull your ecu to check for damage.

 

Now the only code I'm pulling is for a bad oxygen sensor. I'm not an expert, but I didn't think a bad O2 sensor could cause these problems, I figured a misfire when it was cold was about it. Could it be the bad 02 sensor? or am I missing a code?

 

now that that's out of the way, i thought some o2 sensors help control something to the engine before the car warms up, so i guess it's possible?

post up the code(s) and i'm sure someone smarter than me can help you out. i'd address the code before moving on anything else

 

Hey Mars,

I was having similar problems to you on my 00 SE MT a while back. This worked for me, but it may not necessarily work for you.

When I would decelerate and engage the clutch, the rpm's would drop, but every now and then, it would stall because the rpm's dropped too low. Also, the problem started getting worse when I would start the car (after it was warmed up) and it would rev up but then die again since the rpm's dropped too low. I wasn't getting any codes and no SES light.

I replaced the MAF sensor.

Do yourself a favor and only get OEM. Try courtesyparts.com. Fast shipping and reasonably priced OEM parts. I tried aftermarket in the past and ended up replacing the MAF again after 10K miles.

Remember to disconnect the battery so the ECM will reset. Now - this is not an ECU "reflash" or "reprogram" which is recommended after installing the new MAF. I think this can only be done at the dealer unless you have the diagnostic tools.

While I was replacing the MAF, I took apart the throttle body and IACV. Man, that thing was disgusting. Quite a lot of build-up in the TB. Save yourself the headache in the future and take the TB out to clean it so you can get at both sides (as opposed to just spraying cleaner on one side and wiping it with a rag). Be sure to open the TB and clean around the disc. A lot of build-up gets there which prevents air from coming through at idle which may be the source of your stalling problem. After cleaning it, you should be able to look through it and see a slight sliver of daylight around the outside.

Since I had it out, I also replaced the TB gaskets. Probably unnecessary, but it had over 200K miles on it, so it didn't hurt.

I also implemented the coolant bypass with a barbed brass coupler from HD to prevent frying the ECU with a bad IACV in the future.

If your IACV is bad, then putting a new one in may not work if your ECU is fried. Since you're not getting any codes and you're not getting an erratic idle/limp mode, your ECU is probably still good. IACV may still be all right as well.

If you're cheap (like me ), try cleaning the TB first. If that doesn't work, replace the MAF.

Good luck and post any results to help others in the future!

 

Also, to comment on what cornholio said, it was my understanding that the ECM uses the TPS when it is cold to control the engine and then when it's warm, the ECM uses an 02 sensor. If you're having idle problems after the engine is warm, it could be a bad O2 sensor.

These go bad over the life of a car. Not too hard of a DIY. I have done this in the past. Just need the "special" socket with a notch in the side to slide the wire through.