OK to shift to neutral when engine shuts off and still coasting?

[c good]

Hi All,
I still have a problem with my PCM1 Fuse 28 randomly blowing and it shuts off the engine. Is it best to just leave it in drive and coast to a stop when this happens? Or should I shift the transmission into Neutral and coast to a stop.

Dealer had it for two weeks and could not isolate the problem. We are pretty sure its a bad coil pack but they wanted to replace them all for $1200.00 No thanks. I just replaced them 4 years ago when I had a similar problem.

I currently have a 10 amp fuse spliced into each coil pink lead (positive 12v). Am waiting for it to shut down again and that should tell me which coil is shorting out.

 

[Mooseman]

I'd throw it into neutral as it might still be spinning the engine on compression.

Never seen that before with the PCM fuse blowing randomly. Have you tried replacing the PCM with one from a junker? It's possible it's dying. No need to reprogram, just a security relearn which takes 30 minutes.

 

[c good]

Dealership was very understanding and did not charge me as they were not able to diagnose the problem after having the Envoy for two weeks. Their best guess is that it is a coil pack shorting out. I have wired a jumper harness with a 10 amp fuse into each hot lead of each coil pack. If it truly is a bad coil shorting out, the fuse will blow on the bad coil. Or it will at least isolate the coil and/or wiring that is causing the problem. Will keep everyone posted.

 

[Mektek]

No problem with coasting for a while in neutral. You don't want to go for long distances (eg. towing) because there is insufficient lubrication for the transmission without it's internal oil pump running.
Good idea with the fuses before the coils . 10a may be too big, probably 5a is closer to the actual draw. But usually when the coil fails it just goes dead, not a random short to ground.