1992 Toyota Pickup and cold weather

I tried that a while back, but it couldn’t hurt to try again. I’m not sure if there’s an air temp sensor in there either. One time I took it apart and looked at it for something else, and I don’t remember seeing one in there, but again I wasn’t actually looking for it.

I’ve cleaned the throttle body because when I bought the truck I had trouble with it for awhile trying to stick closed after it sat overnight. I hadn’t cleaned the IAC because I wasn’t sure how it worked until I just looked up a schematic on it. I knew fuel injected engines had to have that function, but I didn’t know how it was accomplished. I have checked for vacuum leaks but didn’t see anything obvious.

I also looked at the MAF sensor again today, and I think that there is an air temperature sensor inside of it.

Right now the weather in California is beautiful and the truck is running great, so it might be awhile before I can really put any results to the test. I’m going to take the intake apart all the way up to the throttle body, go back over that as best I can and clean the IAC, see if that does the trick.

Thanks for your help. You’ve reinforced some of the things I’ve already done as the right route to take and your suggestion on the IAC was a solution I’d been trying to figure out for some time – but as a DIYer and only knowing theory and not what the parts are called, sometimes I find myself stuck.

I got back around to this project after having been on vacation, work, etc… Weather here has cooled down into the temperature range where I’d been seeing the issues. A couple weeks ago, I cleaned out the IAC with MAF cleaner really well and completely took out the idle set screw. That and the socket it screws into had a ton of deposits built up in it and I think I was able to get them all out. Since then the hesitation problem has disappeared, but I was having high-idle issues. Figured that out too. Where the linkage connects to the throttle body, there is a little damper that the linkage connector hits when you let off the gas pedal. The function of this piece appears to be keeping the throttle plate from jamming shut all at once, choking off the engine if it’s still under load. Anyway, the thing gums up from time to time. I’ve had the truck since 07 and I’ve had to clean it a few times. All it does is force air through a small hole so that the piston goes down slowly, and thus the throttle plate closes slowly. Anyway, got that figured out and the truck’s running better than it has since I got it. Just wanted to stop by, say thanks and let you know that your help was definitely put to good use.