94 silverado 5.7 - miss came back !!

[silver100]

i put in the ac delco plugs and accel 8 mm wires and a new coil , the miss went away and it ran great . i rechecked the time and made sure it was set right on zero and the miss came back . the same miss at idle . my question is why did it run so good for a few days and then come back , also about the timing . is it possible that the pully that the mark is on could be off and maybe i should do a top dead center time to maek sure it is right , also how do you do a tdc time . any help appericated . thanks silver100

[derekbitt]

is the distrbutor hold down tight?
TDC - remove #1 spark plug stick your finger in there and feel for the piston to be TDC. Before you do this unplug the coil and remove the drive belt you should be able to get a socket on the crankshaft snout nut and turn the engine by hand, dont forget to put tranny in Neutral

or invest in a timing light and a haynes manual.
GL

[derekbitt]

thought about this some more and....
did you pull the rotor and cap off and inspect it, also i would try to see if it is isolated in one cylinder remove cable one at a time and listen , thats what i would do next...

[2000CAYukon]

silver100,
On my K1500, I found that the screws that hold the injector pod on the TBI had come loose. I should have used some loctite. I still have a slight roughness to the idle but the low rpm miss is gone now. At this point, I am not going to replace the ECM (at least for now) and see how things go from here.

I also noticed that the driver's side injector (reconditioned) is dripping a little again so that might explain my idle issues.

It looks like the loose injector pod was causing fuel pressure issues which in turn caused my idle to hunt and for the timing to jump around.

Make sure you fuel pressure is within spec and the injectors have a good spray pattern. Mine felt like an ignition miss but was actually a fuel related miss.

Good luck with fixing your problem.

//2000CAYukon