Ive been experiencing a problem shifting my truck. Its a 2000, ff, b3000, manual transmission, ext cab with about 101000 miles. It usually runs fine but a while ago it began to struggle to stay on when cranked. it would stay on at about 550 rpms until the engine would warm up, then it would rise to the proper rpms. I thought i fixed the problem when i found a torn vacum hose and repleced it. It ran fine for about a week after,now the engine revs high which makes shifting awkward. does anyone out there know any possible causes

 

check your timing,

 

Check the IAC valve.

 

^ ^ ^ +1

 

Reset the computer as well, the adaptive learning recognized the vacuum leak and tried to compensate for the lean fuel mixture. Now that you've fixed the leak it is injecting too much fuel.