I'm no mechanic by far but thanks to this website and chat forums as well as google and youtube, I'm slowly learning so any advice would be greatly appreciated! I bought a used 04 MC SS v6 3.8 and it was a descent running car until I decided to wash the motor and everything around it due to the dirt buildup on it. It took over 3 hours to get it started and running good enough to limp it home. Since then, everything has gone downhill. I've replaced battery, spark plugs and wires, o2 sensor, throttle position sensor, fuel injector, and the thingy two of the 6 spark plugs go in to (can't remember name). Seemed to improve the run/idle issue briefly and then both got way worse. Then traveling home my car would "power up" long enough to reach speed limit then cut out and go down to around 55 mph before picking power back up (was a very long ride home). Was told to replace the engine control unit/power train module so I purchased a "plug and play". Disconnected battery totally swapped computer out, reconnected battery, opened door and got in to start car cause that's what I was instructed to do. All lights and power and no start at all. Would do nothing. Security light blinking. Tried all relearn procedures found here and online and still no luck. Assuming the new computer may be incorrectly programmed I ordered another one. Put it in and same thing. This is my only vehicle and it's been over a week so if anyone has any ideas id greatly appreciate it. I can't afford pulling it to a dealership after purchasing all other parts now

 

Yea there are to much electronics in these cars to mess around and clean the engine like that. I do mine once in awhile but I leave it run while doing it and I have sprayed all the connections I can fined with a clear sealer. My Dad back in the day used dupli-color they made something in the 60's that he used.
I remember when he got something wet he would use an either starting fluid to dry it out, they say WD-40 works good too.
So about 2018/19 I had to have the head gaskets done on a 3400 in my SUV prior to this I replace the 02 sensors and after it was done I couldn't stand the antifreeze smell so I washed the engine I water proofed every thing first, but I would get the check E light and said it was the 02 sensor down stream I replaced 3 of them and finally gave up.

Put the old computer back in and maybe you car will come back.

 

I appreciate the info. I sure didn't think just washing it would end up with this much trouble. Thought I'd give it a good woman's touch of deep cleaning and sure regretting it now. I'm gonna try the old computer and cross my fingers. Thank you for responding.