stalling problems with 1990 GMC Jimmy K5
 

Having problems with my truck, it has the original, bone stock, 200k, fuelie 350. About a month ago it started running poorly, if at all, at start-up. I replaced the ignition module and all seemed well for a couple of weeks, then same thing all over. Tested the module again and this time it tested good but I replaced it anyway. Worked fine the rest of the day, but the next it started acting up again. However, now sometimes it runs fine, but cuts out or dies if you turn a hard corner. Other times it runs fine all day, or like crap all day, or back and forth with no perceivable cause. I have an OTC advanced scanner hooked up to it and it sets a code 42, electronic spark timing circuit or E.S.T.. I have since replaced the E.S.T. module, plugs, wires, cap, and rotor. The distributor was replaced About three months ago due to bad bearings but I checked it again, just in case, all good. Have checked timing, fuel pressure, and fuel injector spray pattern, all good. My computer has a "back-up fuel" setting that effectively bypasses the EST system with a generic spark and fuel map to make it run if need be. So, WHAT am I missing or overlooking? Getting very frustrated, any help is greatly appreciated. Thank you, Kevin.

*Moving to Fullsize K5 Tech* - Please create a new introduction thread in the New Member Area if you would like.

The fact that it cuts out when you turn leads me to believe that there is a wiring problem.

Re: may be wiring
 

Well, I have gone through all of the connectors and all are connected tight, checked all of the harness for rub through for a short to ground, still not finding it.