1991 ranger rpms vary

[Tolein]

I have a 1991 2.3 ford ranger and I have a bit of an issue with the engine rpms. At idle somedays the engine will idle at 700-800 rpms but most days it idles at 1000 rpms. When driving down the highway at speeds around 60 mph I will be running 2500 rpms some days and about 2300 rpms on other days. Does this sound normal? I am curious if the IAC valve could cause this or maybe a valcum leak. I'm not real mechanicly inclined but I have replaced my o2 sensor at the header and cleaned my MAF sensor recently.

Thanks

 

[JamesD]

I would inspect all vacuum lines and replace them if necessary. With truck this old its not unlikely most of them are dry rotted. Vacuum leak can cause idle issues.