revs surge

[almostJDM]

ok, this is not my car but my younger brothers, he has an 89 accord coupe with an auto trans, and when he just sits in park, and neutral the rpm's go up and down but once he is in gear it stops, coolant is good, it doesn't have a CEL, could a dirty IACV cause this?, or even a vacuum leak?

thanks

[jhondayaaj]

What's the code?

[BLUBB2]

ok, this is not my car but my younger brothers, he has an 89 accord coupe with an auto trans, and when he just sits in park, and neutral the rpm's go up and down but once he is in gear it stops, coolant is good, it doesn't have a CEL, could a dirty IACV cause this?, or even a vacuum leak?

thanks

Sure can, IACV, FITV and air pockets in the cooling system are possible culprits.

[TracieS]

Try cleaning IACV. I did mine and mine stopped so give it a try.