I just changed the alternator and after it was replaced the RPMs started to go up and down while stopped at a red light or while in park. When I am driving, the car is fine. Now today the car just completely shut off while at a red light and now it doesn't stay running unless I give it gas and try to take off. What could be the potential problem? Also I have an oil leak that just recently started just for some background on a potential pre-cursor to this problem. Any replies are appreciated.

 

Believe it or not, first thing to do is check your antifreeze level. I just worked on a Civic that would do the exact same thing.

 

Tim is right... your jumping idle is due to low coolant and your t-stat and IACV isn't submerged in coolant to heat it to get it properly operating... when coolant is low and there is air in the system, it cannot process the air so it screws up your idle...

glad to have you back Tim!!!

 

I'll check the coolant and update later if this works. Thanks a lot!!

 

I added the coolant but that was not the problem. The car is doing the same thing. My dad said the idle sensor or something may have failed. Would that cause the car not to start? I am really at a loss so any suggestions would be appreciated.

 

***The car starts but does not stay started***

 

For the heck of it, try wiggling the key around in the lock once the car is running, and see if it shuts off. Possibly a bad electrical portion of the ignition switch, if it doesn't run.

Your dad may be on to something, though. When you start the car, how long will it run before it dies?

 

A closed idle air control valve (IACV stuck closed due to grime) will cause your symptoms. If check engine light is on, you may have an electrical failure in the IACV solenoid drive. If no CEL, then clean throttle plate on both sides, throttle bore, and IACV carefully w/ throttle body cleaner. Do not wet the solenoid w/ cleaner as this will damage the windings.

good luck

 

The check engine light is not on and my dad did say something about the idle so I'll check that out and update later. Thanks for the suggestions

 

I had a mechanic clean the throttle body and the IACV and the problem was not fixed so he is running a diagnostic today and is going to find out the problem. The check engine light was not on when he began cleaning the TB and the IACV but after he finished the light was on, so im guessing the IACV has failed.

 

Let us know what happens because I might be dealing with this problem as well.

 

Look I found this http://www.iapdirect.com/product.php?productid=42003 maybe if it pertains to your problem it involves the throttle position sensor if thats your case. I wonder if anyone has ever used one of these though seems cheap and easy to install.

 

The mechanic figured out what was wrong with the car. First start out with the cheapest problem. My car had three problems: the vacuum hoses, possibly idle air control valve (65.00 on ebay versus 299.99 at any auto parts place) , and a major oil leak on the rear seal and oil pan. The mechanic gave me a quote of 1900.00 to get the things fixed, 1400.00 of that was to fix the oil leaks alone. I advised the mechanic to change the vacuum hoses and voila!!!!! The car works perfectly fine and it cost me $159.62 (which is extremely high seeing that vacuum hose costs about 1.75 per foot). This could be a DIY job if you can manage. I have already put the car into another shop for the oil leak and he gave me a quote of about $600.00. Hopefully this helps anyone dealing with the problem that I had. Thanks for the suggestions

 

You never specified if you have a 2.5 or 3.2 TL.

The 2.5TL has a couple of notorious oil leak points which can look like rear seal, but are not.

First is oil filter adapter extension. There is an oring between the adapter and block that leaks oil pretty heavily. You should be able to spot this leak at the seam between adapter and block. Relatively easy to fix, but access is tricky.

Second is distributor external oring seal and distributor internal shaft seal. I have replaced external oring on my 2.5TL, but internal shaft seal has not been replaced. It is not designed to be replaced, but can be done w/ major surgery on the distributor. I've done a spare distributor, but have not installed. PM if you want the procedure.

good luck

 

Any specific vacuum hoses or just all of them

 

I'm having the same issue with my 98 3.2 the rpms jump between 600-1000 on idle. My mech said it might be an O2 sensor on the exhaust. The motor is a jdm with 55k I just put in.

 

the vacuum hoses going to the intake were cracked and he had to replace all of them so the same problem wouldn't occur again. So hopefully this helps

 

Today my car having this problem (3.2 TL, 1996). The RPM jumping up and down. The problem cause radiator hole was broken.
Cheer~