high idle in 1991 civic 5 speed

 

how high is it
and do you want it lower ?
its supposed to be at 700 rpm from the factory but now 27 years later
900rpm is the sweet spot

 

it is about 1800 and higher as soon as it warms up, when stopped at a red light it won't slow down even in neutral, we don't drive it now as it has been in the family since new and don't want to blow up the motor or have an accident. We had the timing belt changed and a new mapping sensor by mechanics and they just don't know what to do with it so want to try cleaning and checking on our own a few things before putting a bunch more money into it and they still can't figure it out

 

the most likely cause for a high idle is a vacuum leak

 

Thank you for your reply, anything is helpful!

 

thats more than likely what the problem is going to be
now do you know how to check for vacuum leaks?

 

 

1800 over is a lot to be needing adjustment, if it started after service was done.

Sounds like a leak was made. Just listn for hissing and look around for loose lines,.