Envoy is running on highway and suddently turn off & wont start

I wonder if the Immobilizer is related to the door locks and the fuse blowing broke the pairing. Try the reset

https://www.google.com/search?q=2005+GMC+Envoy+SLT+reset+security

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https://www.transmissionrepaircostguide.com/topic/no-reverse-2002-gmc-envoy-slt
http://www.fixya.com/cars/t13849301-03_gmc_envoy_will_not_go_in_reverse https://gmtnation.com/forums/threads/2003-trailblazer-ext-wont-move-when-engaged-in-drive-or-reverse.9590

It sounds like you have a grounding issue somewhere. Look up a fuse diagram for the cabin fuse panel. Start from there.

2002 Envoy sle 4.2 L straight 6. Random misfire(PO300). After erasing codes for several days, I finally took my car on the highway and ran it at high speed(70+) for about 4 to 5 miles. Check engine light came on as before but this time it gave me(PO305). Random misfire cylinder 5. So I switched coil 5 with coil 2. Went back out on the highway and repeated as before. This time it gave me(PO302). This was telling me I had a bad coil. Replacing one coil pack solved the problem. The professionals told me low fuel pressure would not give me random misfire, but rather a O2 code because the engine is running lean. Thank you------------------------------------ thank you very much.

The pressure on the parking pawl in the transmission from the truck being parked on an incline is preventing the pawl from releasing. See if you can get another vehicle to push it a small amount so you can release it from Park position.

I have the same car and the same problem.......

hi this sounds more like you have a flat battery, try getting a jump start from someone and see if that does the trick, if it is the battery you will have to find out why it went flat...hope this helps

It's a nag lihgt to remind you to change the oil.

To reset the warning, turn your ignition key to on, but not start. Pump your gas pedal three times quickly and the light will disappear for another 3000 miles.

sound slike you may have unplugged or disconnected somethine else or the spark plug you put in is bad or inpropper gap

I ran into this concern with my 2002 and my wife ran into the almost identical problem with her 2003. this may sound silly,, but it was the clutch fan. Extreme loss of power from time to time came first. Then a roar of the what seemed like the engine when stopping. Actually cut off after it started to roar at highway speeds, and had absolutely no excelleration from time to time. Sometimes all of the symptoms completely went away. After taking mine to the dealer several times, finally they got it right and replaced the fan clutch. When my wifes 2003 SLt started doing the exact same thing as my 2002 had done, we both knew what the problem was, and the dealer did a quick fix. $600.00. Perhaps this should have been a recall feature, but never was. Everyone that I know that has an envoy, somewhere around the 72,000 and 103,000 mile mark has had this problem and have had to have the clutch fan replaced. It may sound like the vehicle is going to have to be junked,, but that is all it needs.