wtf supposed to run

[the1andonlyGR81]

i got a problem if it were the old days i would def say something with ignition, cap, rotor, wires, but its not all the time the car runs beautiful for like an hour or so of driving,then it starts missing, losing power bad. replaced the coils (not new supposed to be good) boots, i dont get it. woke this morning hooked up the diagnostic on sniper and the ignition voltage was jumping all over but it would idle fine, give it gas it missed a little, drive ok. went to run errands to stay close and sure enough about an hour into it miss, no power give it gas it would do nothing, to the point you have to let it idle to move. shut it off wait 5-10 min it would go again but nothing past 1500-2000rpm stay easy it would go for about 5 min then again nothing. could the plugs act like that? thats what im gonna do anyways just to be new could the egr have something to do the tune says i bypassed it and the second o2 sensors. its the same tune ive run with all my motors im gonna replace all coil and wires just to be sound but if it runs fine for a while it just doesnt make sense.years of mechanical knowledge for myself and all the people trying to help cant come to a solution. any ideas?

 

[slowmkviii]

Start the old way and remove one coil at a time while running.

 

[Right on the Mark]

Any MAF mods? Check and clean that to just get that off list since so easy.

 

[94m5]

http://www.v8sho.com/SHO/CoilOnPlugTest.htm

Test them cold, and Hot. Put them in an oven if you have to.

 

[the1andonlyGR81]

http://www.v8sho.com/SHO/CoilOnPlugTest.htm

Test them cold, and Hot. Put them in an oven if you have to.

thanks for help. what sucks is this is supposed to be temporary while i get c heads ready and intake, in your build thread you powder coated your old intake white,with the red valve covers. did you run that intake with an adapter for the c head or was that all from 'donor motor' pic you showed when you pulled it out. just curious you pulled the c motor out and put it in the corner why did you go back to b head style, just to try the eaton manifold? i was sort of confused what you put in currently.
on my sniper i can real time gauge setup at idle the spark advance needle jumping all over the place give it some gas and it all comes together,but theres something strange there
also there are a few things i dont understand on test procedure
Check resistance from coil pin CD to coil pin B+ of suspect cylinder(s). and i need a diagram of harness for this
Measure resistance from coil driver (CD) pin at PCM vehicle harness connector to CD pin at coil harness connector of suspect cylinder(s).
thanks

 

[94m5]

No, you pull the coils out of the car and test them.


The C-head motor is still being built and will go in after I finish the 3650 swap. The powdercoating is on my current stock engine.

 

[chris2523]

check fuel pressure. if nothing else just to rule it out.

 

[the1andonlyGR81]

where should it be? cold hot the same? idle or under load?

 

[Right on the Mark]

where should it be? cold hot the same? idle or under load?

Fuel pressure should be like 40 psi with vacuum off regulator and like 33ish with vacuum on reg.