Engine/Transmission (1998.5 - 2002) crazy RPM's

[thendrex]

For the past few morning I've hopped in my truck and started it and thrown it in drive and it sounds like the engine RPM bounces up and down irratically. Once I give it the gas it goes away, but I've mostly noticed it when its cold. Is there something wrong with my transmission? I got a new injection pump afew months ago so I'm curious if this has anything to do with it... Thanks guys...

 

[JTBMC]

Mine has also recently started doing this, most often after I've driven for a while and stopped and shut down for 5 to 10 mins, then on the restart it will do it. It sounds like Romp, Romp, Romp, Romp as soon as I put it in drive or reverse and it rocks the whole truck. If I slip it out of gear for a second then back in its OK. I dont know what causes this.

TJ

 

[Lsfarm]

Normal

This is normal. The engine is trying to maintain idling speed, and when you drop it into drive, you load down the engine, it over reacts with a bit too much fuel, then cuts back a bit too much. This goes on untill the engine 'wakes up' a bit and figures out the right amount of fuel to balance the idle speed.



It is much more noticable with the first start of the day.



Greg L

 

[thendrex]

That's the words I was looking for tjlaffite! I didn't know how to describe it! Thanks for the info Lsfarm, I won't worry about it much more then!