nofear5.0

Have an 86 mustang GT, guy that had it before me had 2 batteries hooked up to a norm 60amp alternator, pulled 2nd battery car ran fine, lights dimmed the alternator was bad, got a new one, went to put it on pulleys were diff size thought maybe i could get away with it. I put the old one back on and then the problems started, car bucks 3rd, 4th and 5th gear really bad to the point where i almost go threw the winshield, put new alternator in it still same thing, put new fuel filter in and still the same thing, also put a new coil pack and the same thing has happend, car idles fine except when i hit the headlights on then the car will rev down then back up, car will shut off when i pull the power to the battery, but the alt. tested good so idk... also when the car is running and i pull a wire of the distributor, car still fires on all 8cyl...maybe an ignition module idk could use some help please!!

Tony71502

No it doesn't, unless you have detonation at the exact perfect time every cycle of the motor, it doesn't. Theres no way to get enough voltage to the plug to cause an arc of electricity and ignite the air/fuel mixture without a plug wire. You may have already been running on 6-7 cylinders and pulling the wire off doesn't make a difference because the cylinder already isn't firing.

What kind of ignition wires do you have, if they are not stock and are low quality aftermarket there's a very good chance they are arcing to the block, which will cause some "bucking". Change plugs, wires, cap and rotor is a good place to start.

Need some punctuation when you write, I can't really understand what your saying here.

Are you saying the car idles then engine RPM surges (goes up and down)? Did you have your battery tested?

nofear5.0

Plugs,wires,cap and rotor were replaced about a month ago. We pulled every wire of at a time and the car ran the same, nothing changed. Some guy told me it may be the ignition module. As soon as i turn the headlights on the car will idle down to the point where it almost shuts off, then goes right back to normal...I had the alternator tested and it was fine but when i pull the positive battery cable the car will not stay running


sorry about the first post alot of stuff i had to say

HACKGT350

first you should never pull the cable off the battery while its running you can really fukk stuff up that way. as stated above there is no possible way your car is running on all 8 when you pull the wires off one at a time. are you sure you even have the firing order right? the only way you could have all the cylinders firing with a wire off is if you have detonation like tony said. your car must run like crap if you pull a wire and nothing changes

nofear5.0

well duh of course it runs like crap the whole reason i am posting my problem.. car ran fine except for the headlights dimming and what not, so i went to change the alternator and thought i could maybe get away without doing a pulley swap and couldn't so i put the old one back on and thats when it started with all the bucking, car will run ok in 1st and 2nd then once it hits 3rd 4th and 5th car bucks like crazy....car ran great until i pulled the alt and put it back on.

Tony71502

Can you define what you mean by bucking? I don't know the firing order off of the top of my head, but definitely check that and make sure your wires are on the right plugs. What wires did you use? OEM or aftermarket? Like I said some after market wires have crappy insulation and can end up arcing to the block or even other spark plug wires.

I installed some 9.5mm wires a looong time ago on my car and it was acting up when hitting it full throttle. I put the OEM wires back on and just used the 9.5mm coil wire until I put my MSD's on.

SonicBlueFiveSlow

HO firing order is 1-3-7-2-6-5-4-8.

nofear5.0

car will start bucking around 3k rpm to the point where it will actually chirp in gears 3rd to 5th. found an old post and the guy described his problems which where the exact same as mine, he had some bad grounds which is what i thought from the beginning so im gonna check all that out and see what happens idk