dangt88

hey guys i'm running a 1987 mustang gt the problem is when i floor it and get to 4500rpm the car starts to cut and hesitate and that pisses me off cause i've changed the plugs,msd wires, msd rotor and cap and fuel filter and new air filter and still does it the car just been timed at 13deg. runs very strong but when reach 4500-5500rpm cuts. thanks and what should i check??? please help me

67mustang302

What's your plug gap at?

dangt88

my plugs are just new plugs i've bought for that car just bought them and put them in i just ask the guy at the counter for plugs for a 1987 mustang w/5.0 engine they are autolite 25's one thing i've noticed i've removed a plug and i ain't no mechanic but my god do they look so white.

67mustang302

White ans in porcelein is white, or white as in really white deposits? If they're like white deposits/discoloration it could be an indication of running hot. Check the plug gap first, if it's too big it can cause the plugs to run hotter, and you can get high rpm misfires. What's the timing at as well(total timing)? Make sure the ignition is set properly, then if it still has the problem I'd suspect fuel. Are you sure you have the right fuel filter?

dangt88

the plugs looks like there still new no changes at all.... and by the way what gap would you put? no deposit at all on them no changes from new.

67mustang302

I have no idea what your gap should be. It's gonna depend on the setup.

And the plugs are white as in they're clean? If they look new but nothing appears to be affecting them, then you're rpolly fine. It can take some driving before you start to get buildup on the plugs you can read.

dangt88

plugs been gapped at .050 and still does it i've tried gradually flooring it and does not cut evenbetween 4500-5500rpmbut as soon as i floor it, it cuts constantly please help me guys what to look for??????????? is it fuel problem or fire problem???

van-swink85

Could be fuel pump is weak or maybe a bad pressure regulator

midlifecrisis1

I have an 88 gt that is stock and mine does the same thing. I replaced the cap, rotor coil. Not much of a difference. My motor seems to fall flat on it's face at about 4000 rpm and it gets aggrivating that I can't achieve the true potential of the engine. I am going to do some other replacement stuff on it like the filter and and a few other things. I will keep an eye on this posting to see if anyone has a definate solution to the problem, if I figure it out I will post it on here.