86 GN cuts out and miss at light throttle

[timdesu2000]

Hey Guys, sorry for the long delay. I haven't had any free time lately to try to diagnose the car. I finally got a bit of time this evening. I hooked up my lab scope and watched the cam sensor pattern. The car is getting bad enough now that I can load up some and it will act up in the garage. After it warmed up for just a minute it started cutting out real bad but the pattern didn't drop out. When I was getting read to scope the MAF I got a CEL. I scanned and I have a code 42. EST bypass circuit. I had this code way back when all this started. I replaced the Ignition module, the ECM and added an ignition hot wire kit. I also ran a new EST circuit and a new EST bypass circuit. I have checked the grounds to the ECM and made sure the module and bracket are both tight. So it looks like I need to try and retest the code 42 and maybe that's where all my issues lie. If you Guys have any other words of wisdom of anything else that can cause a code 42 let me know. I think its at least getting bad enough I can now readily duplicate and hopefully find the problem. Thanks,
Tim

 

[TurboTGuy]

This might help. Or not.

http://www.turbobuick.com/threads/code-42.248542/

 

[TurboBuRick]

By chance are you running non resistor spark plugs?

 

[timdesu2000]

I have cr43ts ac delco plugs. They are resistor plugs. I was looking over the wiring again tonight. The code is setting right away now so that should help in tracking it down. As I was looking at the schematic I see I have a tan with a white tracer at b on the module and d5 at the ecm. The schematic says it should be tan and black? Im guessing its just an error in the schematic or a change in the harness during assembly at some point. Anyone else run across this?
I ran a new EST circuit to replace the tan with a white stripe but no change. Code 42 came back after about 30 seconds of running. I will try to get enough free time this weekend to run the flow chart now that the code is setting all the time.
Thanks again.

 

[TurboBuRick]

I have seen that before. Not all the wire colors are correct on the schematic.

 

[timdesu2000]

Hey all, sorry for the long time since an update was posted.
Ok. I ran both est wires from the ECM to the Ignition module and also replaced the ignition module 2 more times. The first one I bought was defective right out of the box and had no spark at all. After all this I finally had a chance and decent weather to drive the car some. Put 50 miles on it yesterday and all was good. On my first test run I had high boost and found I had a hole in my boost control hose. Got that replaced and all seems to be good.
Thanks for all the tips and lets hope the GN continues to run like it did yesterday.
Thanks again,
Tim

 

[GNRick]

Do you recall what brand module was on the car? What brand did you replace it with?

 

[timdesu2000]

All three were GM modules. Why I was so perplexed but I guess the build quality isn't what they were. The first module had a few thousand miles on it and had slowly gotten worse in how it acted. I hope this one lasts longer.