Old problem never solved.
Senior Member
Joined: Jun 2010
Posts: 605
Likes: 0
From: Camden, Alabama
I believe I have the same problem with my 90 5.0. Under acceleration it is fine... but when I coast or am at part throttle it starts to hiccup. I replaced the wires, plugs, cap n rotor, and put a new 48,000V coil on it. I am running E3 Diamonf fire spark plugs and grenatali wires. The rest is MSD. My stereo has recently started to go dead for a min if I suddenly let off the throttle, then comes right back on. It used to be that it only would affect my ipod, which plugs directly into the headunit. It has never died, but behaves like not all cylinders are firing.
Mother Trucker
Joined: Jul 2009
Posts: 887
Likes: 8
From: Roggen, Co
Do you have the msd ign box too? If so try taking it out of the loop. I have a 6a and had to leave it off. I kept getting a nasty miss as well. Took it off and fixed it. But that was just the control box. I think it was a faulty box.
Jez
Joined: May 2010
Posts: 14
Likes: 0
From: MD
I have the exact same problem! Also it started after i changed plugs, cap, wires and rotor. The only code i get is 172 when i do the test but its a pending code as the CEL has never come on with a hard code. New IAC, cleaned egr and replaced manifold tube as it was cracked, no vac leaks, fuel pressure is within speck, new msd coil, new stock thermostat and o2 sensor . I also get slight detonation under load and partial pedal. i was about to pull the injectors next.
94 351w Speed density
94 351w Speed density
Last edited by JezClay; Mar 12, 2011 at 03:35 PM.
Senior Member
Joined: Jun 2010
Posts: 605
Likes: 0
From: Camden, Alabama
If you were talking to me, no I dont have an MSD ignition box. I assume I have the stock box, where ever it is... The wiring is just a big mess under the hood as the box or panel that normaly holds everything has been broke all to hell. Not sure what any of it does.
Senior Member
Joined: Nov 2010
Posts: 208
Likes: 0
From: Toms River,NJ
I have the exact same problem! Also it started after i changed plugs, cap, wires and rotor. The only code i get is 172 when i do the test but its a pending code as the CEL has never come on with a hard code. New IAC, cleaned egr and replaced manifold tube as it was cracked, no vac leaks, fuel pressure is within speck, new msd coil, new stock thermostat and o2 sensor . I also get slight detonation under load and partial pedal. i was about to pull the injectors next.
94 351w Speed density
94 351w Speed density
Mother Trucker
Joined: Jul 2009
Posts: 887
Likes: 8
From: Roggen, Co
Well it's purdy weird Everyone had this prob after you did cap rotor plugs and wires...so it's obviously one of these things that's causing it. I'll be damned if I can tell you which one tho...it's sure a stumper.
Squishy Heads
Joined: Jan 2011
Posts: 1,473
Likes: 8
From: Stafford, VA
They have a tendency to melt holes in pistons and foul after like 5k miles. They are overall a crap plug to be honest. They are cheaply made and they all have some kind of little imperfection. The company should be ashamed charging so much for a product that is flawed right out of the package.