Runs good then starts to miss

[hotairgnx548]

The engine in my signature abruptly stopped left me stranded and going home on a hook. Changed several things and the no start issue is gone. Now it runs and sometimes starts to miss. Hole #3 thermo gun showes not any heat after 2500 rpm for several minutes other cylinders about 500 degress. NGK UR5 @ .030 show strap yellowish color and electrode white so I put in some A/C 43ts @ .030 car seemed to run good then started to miss. My question is when checking for a dead hole pulled plug off at coil pack lots of spark danceing around ( in the GSCA EXTRA there was an artical about this destroying the coil pac any one agree ? Is my coil toast?Thanks John

 

[earlbrown]

Sounds more like a mechanical problem or an ign module.


Is the #3 plug wet with fuel?


Got any metal or antifreeze in the oi?l

 

[hotairgnx548]

Earl ...oil is fine the #3 plug was wet (Are you thinking injector) when I pulled it to put in the ac 43ts plugs. Have put 3 different module and coil pac on it including a new one and 2 known good units they all OLM out good. I'll pull one of the new plugs tomorrow. I'm at my wits end screwing with this thing. Any comment on Richard Lassiter's comment on burnt coil pac when you pull plug wire off? Thanks Earl. John

 

[hotairgnx548]

Earl ...oil is fine the #3 plug was wet (Are you thinking injector) when I pulled it to put in the ac 43ts plugs. Have put 3 different module and coil pac on it including a new one and 2 known good units they all OLM out good. I'll pull one of the new plugs tomorrow. I'm at my wits end screwing with this thing. Any comment on Richard Lassiter's comment on burnt coil pac when you pull plug wire off? Thanks Earl. John

Just got the problem resolved with the miss it was in the 7 way connector to the injector harness we put a plastic zip strap to make sure the connector stay full engaged. I guess these almost 30 year old wire Harnesses can't be trusted. John