2003 Tahoe, Reduced Engine Power

Maintenance/Repairs
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1

I have a 2003 Tahoe that I love but is driving me crazy with a “Reduced Engine Power” message. I am driving along and suddenly it dings at me, the message center says “reduced engine power” and I am losing speed. It goes into a “limp mode” in which I cannot accelerate, it cannot pull itself up a hill, and the engine misses badly. I can pull over, shut it off for a couple of minutes and then start it up and run again just fine until it decides to do it again.

There seems to be no rhyme or reason, one day it did it 4 times w/n the first 20 miles, then ran 100 miles w/o doing it at all. I recently took it on a trip that normally takes me 1 1/2 hours, it took 2 1/4 hrs that day because I had to pull over so many times. I was having to stop every 3-4 miles by the time I got there.

My usual mechanic has completely given up, told me to trade it. I have had it to another mechanic for over a month now, 3 times he has thought it was fixed, but it wasn’t. One time, I didn’t even make it the 5 miles to my house before it acted up again.

One other note on this: this past trip I made, I left early in the morning and my lights were flickering high/low. . . this went on for several miles. Finally my lights quit flickering, then I lost engine power, pulled over, shut it off. When I started it back up, the lights started flickering again. The cycle seemed to continue, once the lights would settle, the engine would lose power. I took it to a parts store and had the battery and alternator checked. They said both were fine. (Had never noticed the light thing before, but I can’t think of a recent trip after dark.)
Anyone have any ideas that I can pass along to my mechanic?

2

You need to try to give everyone a run down of everything and anything the mechanic has done to check things out. This should include any basic “tune up” type of work that has been done (e.g. plugs, wires, filters…) Otherwise we’ll all spend a day saying “check this” and “look at that” and you’ll spend a day saying “oh, my mechanic tried that already.”

Included in stuff your mechanic did there must have been some computer scanning going on. At the very least there must be some error codes coming out of the computer & people need to know what the codes are (the exact specific codes like “P1234”). Ideally there has also been some real time scanning of engine parameters. Any & all info you have about that is helpful.