1998 GMC Suburban Power Loss/shutdown while driving

JIMB2CARPROS

MEMBER
1998 GMC SUBURBAN
V8
4WD
AUTOMATIC
115,000 MILES

My 1998 GMC Suburban recently had a radiator replaced. Since then I have driven on 10 occassions (100-200 miles under various conditions). 2 times now the vehicle has died while underway, once it was actually more of a flicker of the lights a few times and loss of power but it rebounded. The second time it died completely while traveling at 45 mps with no obvious indicator of the trouble. I did notice the speedo was stuck at the speed I was going until I turned off the ignition and restarted it. It started up on the second try and I was able to get it to where I was going, and start it up the next day to drive it to the shop.
The GMC shop has said the car did not throw any diagnostic code and is at a loss to diagnose without experiencing it. They were able to start it and keep it running with no issues so far.
Any ideas you can provide would be much appreciated.

3 Replies

FACTORYJACK

MECHANIC
4,159 POSTS

Without duplication one can only guess at the problem. It could be losing spark due to a faulty coil, or ignition control module. Has the vehicle had any tune related maintenance, what is the condition of the coil wire and distributor cap. I would think that if it was losing fuel pressure, that it would get sluggish prior to dying as the pressure bled down, it sounds more like your experiencing a shutdown almost as if someone shut off the key. The unfortunate part(fortunate for you) is that it restarts rather quickly. If it took a little time, and had to cool down, one could develop more of a hypothesis, or even get a chance to do some quick check diagnostics. If you get the opportunity, I would check for spark first.