93 Toyota Camry Engine Problem??

I have a 1993 Toyota Camry V-6. This past week it's been acting up a little bit. When it's warm at idle sometimes it will drop to like 400 rpm's and the steering wheel vibrates. It's however not an erratic idle and it maintains itself at 400 rpm's. It doesn't stall out either. Not all the time it does this. Just a few times. Then sometimes it will restore itself back to 750 rpm's. But the check engine light hasn't come on. However the light is functioning ok. Other than that it's been running great. Any suggestions??. Thanks.

Check spark plugs & timing. (10*btdc in diagnostic mode - Diagnostics port, bridge E1 & TE1)
Check that the cold-start injector is spraying on a cold idle, but not on a warm idle.
Check fuel pressure @ idle.


If the ignition timing is off, or compression is low; check cam timing also as the belt probably sliped & needs replacing.

Check spark plugs & timing. (10*btdc in diagnostic mode - Diagnostics port, bridge E1 & TE1)
Check that the cold-start injector is spraying on a cold idle, but not on a warm idle.
Check fuel pressure @ idle.


If the ignition timing is off, or compression is low; check cam timing also as the belt probably sliped & needs replacing.
Hello, you might also want to check to see if the ISC (idle speed control valve) a.k.a. (idle air control valve) IAC is gummed up and needs to be cleaned or replaced. I believe this part is partly responsible for a smooth idle at the correct r.p.m.'s. I feel since the car is acting up the way it is; it could be caused because the IAC/ISC is in need of cleaning/replacement. If I am wrong someone please correct me :nono: :2cents: :feedback: :banghead: JOET/CAMRY

Thank You all for the tips. I pulled out my Chilton and was researching the problem and I was shooting towards the IAC valve as well. I thought the computer would put up the check engine light though. Anyway I'm a bit bummed the manual says I have to take off the whole throttle body to replace it. I was thinking maybe I can somehow replace it without doing so. If someone knows a better aproach without having to take off all that junk that would be great. I have the V-6 3VZ-FE Engine.

Thank You all for the tips. I pulled out my Chilton and was researching the problem and I was shooting towards the IAC valve as well. I thought the computer would put up the check engine light though. Anyway I'm a bit bummed the manual says I have to take off the whole throttle body to replace it. I was thinking maybe I can somehow replace it without doing so. If someone knows a better aproach without having to take off all that junk that would be great. I have the V-6 3VZ-FE Engine.
Hello dyna,You shouldn't have to replace the IAC valve. :smile: all it needs is a good cleaning. search the forum for IAC cleaning. go to camry faqs and information on page 3. On your engine (3vz-fe) v6 the IAC valve is located on the throttle body near the firewall. it is held on by 2 12 mm bolts. remove the part and give it a good cleaning. make sure the part inside moves freeley when you clean it. when I cleaned my IAC valve on my 1989 Camry I used carburetor cleaner at first then used wd-40 to lightly lubracate it. have had no problems since. good luck fixing your car. :) JOET/CAMRY

Thanks Alot for the info JOET. When I have a chance I will tackle the task. I was going to post this when I wrote but know that I know it's probably the IAC valve. Does that have to do with gas mileage. I get very poor gas mileage on my Camry. Although the spark plugs, wires, and a bunch of other stuff are brand new. I checked the tires and pressure thats fine. Also the brakes aren't dragging. Plus it just passed inspection so it can't be running that rich. Im currently getting around 14MPG. It has an 18.5 gallon tank and I get about 200 miles to a full tank.

Check your ECT sensor. It will make you run rich. If your engine is running smooth - rich is the most likely answer. This would explain your erratic hot idle.