charter35

i have 1990 mustang lx 5.0 has 200000 miles few bolt ons recently change cap and rotor and plugs the autolites and when i get on it hesitates and sputers at about 4000 rpm but if you stay on it stops. only seems to do it once it warms up timing looked ok when i checked it and fuel pressure set to 40 idles fine was thinking maybe it was the cap and rotor or the plugs but have not had time to pull the plugs

thanks

stanglx2002

Sounds like the timing is off. get a timing light and see what your timing is at and set it to about 12 degrees. also when you set the timing readjst the tps between .98 to .99 for better throttle responce

sastangman

check the gaps on the plugs,also what sparks were you using
before you put in the autolites???

wildstang87

i would agree with sastangman, sounds like you gapped them too wide. the specs are .47 to .52 but i usually run about .42 to.45, autolite 25s only.

stanglx2002

the stock gap is .50

wildstang87

actually .47 to .52 but ok, like i said mine runs better with around .45. i might have a weak coil though. you never know til you try it. it just sounds to me like you might have gapped them too wide and the spark isnt strong enough to make that gap.

charter35

i had bocsh platinums in before. i think there the autloite 25 need to check, with the other plugs had timing at 12 or 13 need to check again have an accel coil. will have to check this weekend

thanks for the help

charter35

still having problem bought Bosch platinums again that what was in it before, they told me the gap for these is .54 still sputters at 3800 rpms, this is what i had before and it ran fine, still need to check the tps but would that actually cause this problem or could it be something else Distibutor .ignition module both have over 200000 miles on them timing is fine.

thanks

ohh3Ecofire

how about fuel pump problems?...how old is that fuel pump.

charter35

fuel pump is about a year old bbk regulator. regulator set at 40 psi spark plug wires are about 2 years old