frgrandall

ok i got my truck to stop idle hard. But at 45-55 mph under 2100 rpms it starts a bad vibration. And when it is in (D) and you seat at a red light it surges between 1000-1300 rpms never did any of this before my brother and i replaced the speark plugs. could it be a bad coil in the speark plugs? ANy help would be nice thanks

wde3477

It could be any number of things.

This looks to be a problem that you've been struggling with for quite a while - I took a look at your previous post.

Does the 'check engine' light appear now?

For the high idle - suggest to check for vacuum leaks or to inspect the Idle Air Control for crud buildup. For it to be idling that fast in Drive, suspect if there is a leak, it may be significant enough to hear it.

For the bad vibration - based on your previous efforts, I suggest there's still a misfiring issue.

frgrandall

Ok i am planing to do a vac. test this weekend. Someone told me to get it up to the speed were the vibration starts and drop it into (N) and if it keeps it up it would be the drive train. Is this right or wrong? i just need to blow it up lol. jk

wde3477

I would think driveline vibration would be present in varying degrees across all speeds.

Interesting thought, though - heck, give it a shot - it's easy, quick, and cheap enough to try.

Gets back to my philosophy that if you don't know what it is, then start eliminating the things it ain't.