Idle/Hesitation Issues

[92seo]

I have an 86 Corolla that is an excellent, reliable car with only 97k on it. However, it seems to have an idle/hesitation problem when it gets warm. Let me explain.

When the car gets up to normal operating temperature, or maybe even just a little past the middle of the temperature gauge, it starts to run worse than when it is cooler. Sometimes when you push on the gas pedal it bogs down, not really doing much. You can't give it much gas a lot of times when it gets warmed up, or it will hesitate. Then, seemingly when the fan kicks on, the car will shudder for a few seconds.

I tried turning on the AC to see if I could replicate the problem, and it seems to keep the shudder going the whole time, like when the fan kicks in.

So far we have had a basic tune up done, with new plugs installed. We have tried running better gas in it as well. It also has a new battery in it now. Not long ago the mechanical fuel pump was replaced as well.

Any ideas as to what could cause this heat related issue?

[92seo]

Bump..............hopefully someone will have some advice. I can't figure this out, and I don't just want a mechanic to throw parts at it and charge me for them.

[Rookie_One]

what trim do you have?

[92seo]

First, let me correct myself. The Toyota is a 1985 model Corolla. Our 86 Caddy is currently in the shop as well, so I must have got them mixed up in my head.

Anyway, the I think the Corolla is the "deluxe" model. It is a 4 door hatchback, frankly quite ugly, but a good car to this point. I'll try to answer any questions that may come up the best I can if it will result in me being pointed in the right direction.

[90 GP]

Check all the vacuum lines for leaks. Did you replace cap/rotor/ plug wires? Also check your timing in particular check to see if it advances with acceleration. Your idle speed may also need to be adjusted.