My 89 toyota pickup runs great when cold, however, once it warms up it won't go above idle speed. It won't go faster than 30mph and won't rev. Just replaced mass air flow sensor.

 

Is there a check engine light?

 

No check engine light, didn't throw any codes either.

 

Make sure your airtube is hooked up and sealed well. I had a bad leak and it would not let it rev up. I think what is going on is the leak is small enough to operate your Air Flow Meter to let the truck run but a big enough leak not to let it rev.

 

Thanks, will check it out and post.

 

I think it was the "O" ring on my idle screw. It was in bad shape. Replaced it and seems to be running fine now. At least for 2 days.

 

Thanks for letting us know on that. I have heard of it happening, just never experinced it myself.

 

Keeping my fingers crossed that that is what it was, in addition to the mass airflow sensor.