Hi guys,

At my work, it floods often, and creates a giant puddle that you have to drive through to leave. Couple weeks ago when I was leaving, my Jimmy stalled out right in the middle of the puddle. We pushed it off to the side, let her dry for a day or two, blew water out of everywhere we could find, and eventually realized that the ground to the engine block came unattached. We reattached that and she eventually started right up after 20-30 minutes of cranking.

Couple days after I had her running again, random issues started popping up.

The vehicle is a 2000 Jimmy SLS, 2dr, 2wd, 4.3 Vortec, 4l60e, 114k miles.

Here's a list of the issues I've been experiencing:
(All of these problems have been coming and going, as one goes away another comes back)

Transmission:
Hard jerky shifts, not shifting from 1st into 2nd until 2100-2500 RPM's, 2nd to 3rd waits until about 1800-2200 to shift, 3rd into 4th shifts just fine, sometimes lurches and jerks when going from Park to Drive. When cruising on the road, wide open throttle won't cause the vehicle to downshift. (50 MPH in 4th gear with wide open throttle should cause the vehicle to jump into 2nd, it doesn't)

Engine idle:
First starting her up, she cranks and idles around 800 RPMs for a moment, then drops RPMs and stalls. At times on the first start, the engine coughs and sputters because the idle drops to 350-400 RPMs and starts to die out, throttle open or closed doesn't effect this. The RPMs will jump from 350-1.5k trying to find an idle position. This lasts for maybe 10-15 seconds.
(The only way I can start her right now is to start with an open throttle, and keep RPM's around 1.2k-1.5k for idle, wait about 10 minutes at idle, and then put her in gear)

Driving very slow (5 MPH and under), if I tap the throttle and raise the RPMs from 500 to 1k, or so, once the RPMs drop back down, she sounds like she's about to stall out, and occasionally does.

Another issue with the idle, at times, it idles very high around 1100 RPMs. Even while driving (if I am cruising at 25 MPH and take my foot off the throttle, the RPMs drop to around 1,200 RPMs and the vehicle continues to pull forward, instead of decelerating). Sitting at a stop light, with an 1100 RPM idle, the second I let off the brake she's pulling away from me.


To end this all up, what I am considering is that my computer got wet. My passenger side window has been busted, and rains an AWFUL lot here in Miami, and I have yet to cover the window up. Since the computer is right inside the glove box on the passenger side, water/humidity may have worked it's way in there.

Anyway, any thoughts as to what the issue could be would be greatly appreciated.

Thanks and sorry for the long read!

 

This is the EXACT same problem I am having....I'm sorry I can;t offer a solution however, I'm out trying to find an answer myself. There was a huge flood in Michigan (Detroit) and I flooded the engine. Got it started again (changed air filter, dried MAF sensor, changed the eng oil) but it still has the same issues you are having.

Did you ever find out what was wrong?

 

Throttle position sensor! $20 and i'm back in business.

 

Hey man,

Thanks for the response. I was kind of guessing/assuming it was a sensor, but I never got around to further investigating.

I suppose now I need to head out and pick up a new sensor!

Thanks!