Hoping someone’s come across this issue.
New to me 80. At startup, idles at 1600 RPMs. P & N is 1600. Any gear idle is 1000 RPMs.
Another issue is that at startup, when I press the brake to put it in D, the RPMs drop to 900 and surge up to 1200 repeatedly. This stops when I go into D, then it holds steady at 1000. This won’t happen though if I put it back in P and press the brake. But it’ll happen again if I turn the ignition off and start it up again. Every time I start and press brake, the surging happens until I go to gear.
The high idle problem has been going on since after I bought the truck 2 months ago. I didn’t take note of what the idle was when I bought it because I didn’t know what was normal. I learned what idle should be while doing baselining tasks. Among other things, I’ve replaced worn vacuum hoses, cleaned throttle body, intake plenum. Vacuum hoses seem to be ok and the tubes from the air filter aren’t cracked.
The surging happens for a few days then will not happen for a week or two.
I replaced the O2 sensors today since I would intermittently get 25/26 CELs.
Throttle wires aren’t stuck. Ran the FSM diagnostic on the TPS and it checked out OK.
At a loss. Any ideas?
New to me 80. At startup, idles at 1600 RPMs. P & N is 1600. Any gear idle is 1000 RPMs.
Another issue is that at startup, when I press the brake to put it in D, the RPMs drop to 900 and surge up to 1200 repeatedly. This stops when I go into D, then it holds steady at 1000. This won’t happen though if I put it back in P and press the brake. But it’ll happen again if I turn the ignition off and start it up again. Every time I start and press brake, the surging happens until I go to gear.
The high idle problem has been going on since after I bought the truck 2 months ago. I didn’t take note of what the idle was when I bought it because I didn’t know what was normal. I learned what idle should be while doing baselining tasks. Among other things, I’ve replaced worn vacuum hoses, cleaned throttle body, intake plenum. Vacuum hoses seem to be ok and the tubes from the air filter aren’t cracked.
The surging happens for a few days then will not happen for a week or two.
I replaced the O2 sensors today since I would intermittently get 25/26 CELs.
Throttle wires aren’t stuck. Ran the FSM diagnostic on the TPS and it checked out OK.
At a loss. Any ideas?