I have a 1984 Mazda RX-7 GSLSE (13B engine) that I bought brand new in 1984. I have been having a problem with the car that nobody, including the dealers, can seem to determine. Whenever I go on
a long trip and drive for a period of 1 hour plus at a sustained speed of 70 MPH plus the problem seems to surface.

At the end of the trip and when I begin to drive at slower speed in local streets, the idle becomes
erratic and sticks at a very high idle (in neutral) of about 30,000 RPMs. Sometimes the idle fluctuates between about 30,000 RPMs and 5,000
RPMs. When I hit the gas pedal, sometimes the idle goes down to normal but other times it takes a while. This sticking to a high idle persists
for two days or more. After a few days of slow local driving the problem seems to disappear until I go on a long trip again at sustained speeds
of 70 mph plus. Can someone tell me what is causing this problem?

Please let me know what you think the problem may be and the possible solution/s.

I really like this car and would like to keep it for many many more years.

WVERNE

 

Sounds like the throttle is sticking. Do you feel any difference in the gas pedal?

 

You might want to try some throttle body cleaner or inspect it at least.