Engine surges, cutouts, rough running during acceleration - Help Please!


Mar 1, 2018
Columbus MS
I've read many of the posts related to surging/rough idle and have not been able to solve my problem. Perhaps someone here can relate to the same experience.

Background: Did a V8 swap in my 87 Bronco II in 2018. Motor is a 5.0L from 90 Lincoln Town Car rebuilt to Mustang H.O. specs. Have installed Explorer GT40 heads, Comp Cams 35-349--8 camshaft, Comp Cams High Energy Push Rods, Comp Cams Magnum Rocker Arm/Stud Kit, plus a lot of other goodies. Has been running great with NO problems.

This past weekend I installed a 96 Explorer Gt40 Intake Manifold setup; includes the upper and lower intake manifolds and 19lb Explorer fuel injectors. Also replaced the distributor cap & rotor. Ran great for the first 3 hours of operation, then it didn't. On our way home from driving around we suddenly experienced severe missing, engine cutting out, surging, etc. Managed to limp home and have been trouble shooting every since.

Seems to idle ok at first, then gets "rougher" as it warms up. I'm using Accel high output plug wires. I noticed while setting the timing (had my hand over top of wires on distributor cap) I was getting "zapped" by the plug wires. I can grab/touch the actual plug wire(s) with no issue; however, if I put my hand over the plug wire boots on the distributor I get a spark/shock.

Used a mechanic's stethiscope to check injectors. Each injector ticks/sounds the same. They "appear to be working fine.

Fuel pressure - Stays steady at 40-42 psi while running, drops to a steady 38 psi when shut off. Held this pressure for over 30 minutes before I removed the pressure gauge.

Ran a computer diagnosis and got the following results:
KOEO Error code(s) 81/82 - Air Diverter Solenoid Fault. Expected as I have removed all smog related equipment except for a universal cat converter.
KOEO Code 11 - All is OK,
KOER Error code(s) 94/44 - Air Diverter Solenoid Circuit Fault/ Thermactor Air System Fault - Again, expected due to removing smog equipment.
KOER Code 90 - Cylinder Balance Test is good. No issues.

All vacuum hoses "appear" to be on and correctly installed; however, vacuum gauge shows a lower than normal reading. Gauge indicates a timing issue but I set timing using a timing light (correctly).

I'm really puzzled here. Any and all feedback would be appreciated.

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I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
That cap shouldn't be zapping you like that. I set timing on a many a ford and don't get zapped unless there is an issue. If you have the old coil wire throw it on and see how it does.


Mar 1, 2018
Columbus MS
Thanks for writing back. After reading your post I went back for a closer examination and found very small "hairline splits" in many of the plug wire boots. I guess I may be getting some cross-fire as a result, which accounts for the "zapping" I get when I touch them while setting the timing.

I have extra boots that I can use to replace bad ones but think I'll go for a new set of wires and see what that does.

Any suggestion on what type/brand plug wires ya'll think work best?



Mar 1, 2018
Columbus MS
Replaced the coil. Fixed the problem. No more cutting out, surging, etc..

Any ideas what would make a coil fail? Only two years old and less than 12,000 mile on it.

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