99

[topless87]

i have just done valve cover gaskets on a 99 and removed the intake to do so, and now my idle is at about 1500 rpm. i have checked all hoses and sprayed carb cleaner and nothing changes. i can take out the big hose on the side of the intake tube and it goes down. i have checked up and down. would the sensor on the bottom that has the coolant running through could have gotten air in it. been racking my brain any help would be appreciated. thanks

 

[brian2sun]

Was the engine cold when you started it? It's normal for it to idle around 1500 rpms for a coupe minutes during a cold start up.

It is possible that there's air in the cooling system. But first (if the idle doesn't just go back down on its own after a few minutes), I'd try pulling the negative cable off the battery for a about a 1/2 hour to reset the computer. This is common when you mess with the TB and IAC sensor.

If if doesn't go back to normal after a while, you can try purging the air out of the cooling system by popping the cap off the radiator and driving up on something (or jacking the truck up) so that the top of the radiator is higher than the IAC (the sensor on the TB that the coolant runs through). Let it run for a while like that (let the thermostat open up and continue to run for several minutes) and any air should make its way out through the top of the rad.

 

[topless87]

i have done all that and i knew about the high idle on start like an automatic choke. but thanks for the help