93z71

hi guys. finally got my truck. heres the issue. when i test drove it, i felt a shudder and thought tires etc. well turns out it's missing. some times bad, some times just a bit, then sometimes not at all. it even stall out friday morning till she warmed up. thinking dist. or wires,plugs? any other thoughts? it a 93 with a 5.7 with 190 on it.

kevinkpk

This is ob1, is the service engine light on?

93z71

Ya, I had it tested first. Was map sensor. Replaced and reset. Then after 10 seconds came on and says 43. Electric spark control module failure. Looked under hood and can't find it on firewall by dist.

93z71

is it in block case on passenger firewall attached to the pcm? and i know there's one in distributor i was told that's kinda like a u shape. am i correct? i idles ok, but when getting to speed ( above 40) it shakes and surges a little. any ideas? gonna bring it in tomorrow but one place wants $50 to diagnose it.

93z71

anyone?

93z71

took air cleaner off to look at dist and pulled wire from coil to dist and alot of white powder fell out, thinking corrosion. and inside wire on coil side rusty inside. plus wire had a 1/4" long rub/burn mark in it. any ideas other then that to replace?

oleblue92

Sounds like you found it

93z71

No. Just tune up. Update Thursday night

oleblue92

Good luck!

93z71

Turns out it was carbon. On cap/rotor and distributor was loose.