full throttle miss

[859tkw]

i have a 89 gt 306 b cam gt40 heads and edelbrock intake the car runs fine unless wide open 4000 and above this problem just started i have replaced coil, module on dist., cap button and wires and plugs are new any ideas????

[svtmofo]

What are ur plugs gapped at? What plugs are u using? Do u have an ignition setup?

[859tkw]

i forget what kind of plug they are i believe bosch platnum and i dont know the gap on them its has been fine up until the coil went out and it has done this ever since and only thing not stock on ignition is coil and i put a accel module on it but did it with stock one also

[svtmofo]

I have never had any luck with bosch myself. Id check the gap, they may be blowing out at full throttle

[859tkw]

i will check that prob just change the plugs all together what do u recomend?

[Mista Bone]

I'm partial to NGK's in both Ford's and Honda's.

R5671A-x x=heat range.

[blown96cobra]

Autolite 764s I believe are the plugs for cast gt40s

[700hp04mystic]

autolite or motorcraft if no spray is on that beast.

[svtmofo]

Id go NGK's Or Motorcraft. Id stay away from the platnum crap too. Just my opinion.

[859tkw]

ok so i finally got a fuel pressure guage the car holds 42 lbs of pressure but when u rev the car it drops below 30 to like 27 or 28 just reving to 3800! think i found my problem im sure it drops even lower under a load over 4000 what u guys think?

[Mista Bone]

either a clog or bad fuel line, if not time for a Walbro.

[859tkw]

well since last post i have replaced fuel pump and injectors and regulator and fuel pressure is finally great but guess what miss is still there lol. i had a guy tell me today my alternator could have a bad diode in it and if so it would cause a rf signal that could mess with my ignition and injectors through the harness cause they run so close sounds kinda crazy but guess that my next thing to try! anyone else ever heard of this?

[stocknotch]

It's more than likely a ground. You have one behind the battery that comes apart. Its black and looks like it would have a fuse in it. Take it apart and clean it. That should fix it.

[859tkw]

i will check that thanks

[mrstang-gt-46]

PLUG PROBLEM

[859tkw]

doubt plug problem being its had 2 sets put in it and made no difference

[mrstang-gt-46]

.54 gap just sayn

[mrstang-gt-46]

vacume leak pvc

[859tkw]

yea and if it has a leak i sure can't find lol it i used a hole can of starting fluid looking for a leak i have helped build a few of these cars in the past and this is my first one i have had personally and its stressing me out terribly lol getting to the point i hate looking at it

[859tkw]

so thanks everyone for the suggestions turned out the distributor had side to side shaft play and not much at all but aparently it makes a huge difference the car finally runs decent