99 Tahoe..RPMs drop when I go over bumps

[99T-A-H-O-E]

OK guys...Please help !

When I drive over bumps the Tahoe's RPMs drop and you feel a jerk. The RPMs do go right back up. I could be doing 70MPH and let say I hit a bump....the RPMs will drop from 2500 to like a 1000 and go right back to 2500.
The worst is when you go over railraoad tracks.....RPMs up down up down............someone help me.

I have been to 3 shops and a dealer (Paramus Auto Mall NJ)

They told me I need a CKP sensor, Ignition module, and an Ignition coil.
They wanted $800.......I got the parts and told a local shop to put them in....guess what still doing it.

I alos put in a MAP sensor.........no luck.

Tahoe has 160K

 

[clkelley]

Welcome to the neighborhood!

Although I have NEVER heard of anything like this before, I would guess that you have something either loose or barely connected in the engine wiring harness that is exaggerated when hitting bumps. Go through the wiring harness really well inspecting every inch of it to ensure that there are n0o breaks in the wiring or plugs that are not connected properly.

 

[99T-A-H-O-E]

Ok....thanks for your help. The 2 shops did try to look over all the wires.....I have new spark plug wire sets.....I have to up them in and see if it gets fixed.

I hope someone some one can help me, who knows about this problem !

 

[clkelley]

Well, the wiring i am talking about is the engine wiring harness that comes from the ECM.

Let us know what you find...

 

[99T-A-H-O-E]

It's now at another shop......let see if they can figure it out !

 

[lesterl]

Watch fuel pressure when going over bumps, Also with a scantool watch MAF sensor output.