I have not had this happen for a couple of years now, but after washing the Escalade with a sprayer tonight to get the road salt and grime off, the engine was choking and sputtering when I got it out of the wash. Took quite a few starts to get it going where it would stay running (used light throttle pressure to keep it going) on its own. Did some low speed driving around in the parking lot for a while until convinced it would not die on the road (stalled a few more times while doing that!). Finally limped home on back roads in case it stalled for good. Check engine light has been on steady. I called onstar and they report an ECM problem with engine knock, whatever that means.

The engine seemed to be getting more able to accept harder acceleration after about 45 min of driving. I would test it out when on sidestreets with no traffic in case stalled the vehicle. Still big hesitation when really stepped on it.

When this happened before, I though perhaps I had gotten water into the k&n filter up near the firewall. I checked for this 2nite and all was dry. Next thought was maybe I was too vigorous washing the tailpipe and some travelled up system? Doubt it. Third thought, can washing intercooler have any impact? Or maybe got ECM wet? Wires? Ignition?

Now I am going to be terrified to wash the Escalade! I sure hope the problem goes away overnight like it did last time. I need to figure out what I am doing to cause this, so can fix/prevent it in future.

Has anyone else with a procharged vehicle experienced this? Thanks!

 

For completeness, here was the link from 3.5 years ago, but we never really got to the bottom of it.

https://www.performancetrucks.net/fo...-rough-419214/

I am going to start up the escalade to see if I got lucky again and Father Time simply solved the problem for me.

 

It would help if you would scan the PCM and post up the DTC's. Or call Onstar to get them.

Have you ever dealt with replacing and sealing up your stock knock sensors? They are underneath your intake manifold, and down inside the valley cover. They are known to allow water intrusion and corrode really bad. This can wreak havoc on your ignition timing. There are several other places that water intrusion can make things run like crap. Knowing the DTC's will help alot to narrow things down.

Washing your engine bay with a pressure washer isn't the best idea, IMO. There are better methods.

 

Wet air filter...

 

Sorry for my lack of knowledge, but what are DTC's? Edit: Guess = Dealer Trouble Codes? I will call up onstar tomorrow, hopefully they saved this information from when I called them tonight.

And I was not washing the engine bay, just the outside of the vehicle.

 

Perhaps. I just took it out of the garage, and for a spin around the block. When I pulled out of the garage, the check engine light was on. I tried some harder acceleration midblock, and it still hesitated, but then went. Lo and behold, when I turned around to go back home, the check engine light had gone off. So hopefully after a day inside a heated garage at work tomorrow, all hesitation will be gone for good.

 

Sorry, tech jargon. DTC = Diagnostic Trouble Code. Would be something like P0300, P0142, etc.

I must have misunderstood your first post, I thought you were washing off the engine, underneath, and exterior complete.

Where were you spraying, besides the exterior paint? Were you doing the washing, or was this an automated drive-thru wash? Was there an under-body spray?

I've seen water get into O2 sensor harness connectors in carwashes. That makes them run like **** also. Do you still have all four O2 sensors?

 

edit... just saw where you said you weren't washing underneath the hood.

 

Thanks for the clarification - will look into it tomorrow. I am not sure if I have all four 02 sensors or not. Where are they located and what do they look like? Perhaps I could put some type of protection over them?

I was just washing the vehicle with a wand wash at the local car wash. I did spray the front grill at a downward angle but maybe I got too horizontal. Did not do windshield for too long as always fear water getting into air intake which is near firewall. Also sprayed exhaust tip at downward angle.

So it all is a mystery to me. But I am just glad it happened to me and not my wife or I would still be getting torn a new one!

 

Can you post a complete list of your mods on this vehicle? Thanks.