Just built 331 and rebuilt trans.. missing badly at high rpm - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Cdnc93lx · 05-02-2004, 00:10

i need some help people... the mechanic who built my motor and rebuilt my trans seems to be of no help in finding the problem with my car . heres a run down. 331 stroker 24 lb injectors ford motorsport "x" roller cam gt40 upper and lower intake. also had a heavy duty t-5 rebuilt... but as im reading i have come across several sites that have said only use automatic trans fluid in both manual and automatic trans.. well i didnt know that and it looks like the guy who built my trans didnt either. he used heavy gear oil.. now thats one problem that i just stumbled upon surfin thru here that i had on top of the missing bad problem i already had . so i guess what i need to know is between 4500 and 6000 rpm my car misses but not always only when i drive it for a while. is this problem related to the mess up the mechanic made with the gear oil in the tranny im wondering or it is something like need of bigger injectors or upgraded ingnitionsystem .. im lost here ..ive dumped tons of money into this project and its nothin like i had hoped.. the mechanic will eat the repair cost of the mistake he made he says. but can i expect that when he fixes the tranny mistake my problem of high rpm missing to end? like its starving for more fuel is more what it feels like.. any and all comments on this are appreciated ahead of time.. thanks

ebxr8240 · 05-02-2004, 02:16

It could be a few things from valve bounce,runing lean up top,filter or low performace efi pump?To bad ignition leads,cap, too much gap in plugs..
What maf and heads...
Welcome to forums...
Actually ATF is o/k but an additive should also be added..There are light oils out there now made for these box's....

Cdnc93lx · 05-02-2004, 07:44

it has a 75 mm pro m bullet on it and AFR aluminum heads. but still has stock ingnition system. we've checked the gap in the plug several times in fact replaced them twice already with hotter ones just to see if it would help.. no go it didnt work. seems like the only time it runs bad or misses like i described above. is when it gets to normal opperating temp. it has a 180 degree thermostat i read where it said not to go below this as it will hurt performance. ive talked to several people and they seem to be pointing in the direction of an msd ignition system .. which i know wouldnt hurt me either way if it fixes the problem or not i think its still a good idea to try it . everything as far as the cap and wires are brand new should i replace them again just in case?? normal driving this car runs very very strong but when i get into it hard is when it seems to miss like a burbling in the motor is what it sounds like but my tach jumps a lil when it makes this noise so it tells me the fire isnt there.are 24lb/hr injectors ok ?? for this type of setup im pullin my hair out here ...lol after 6000 dollars of car work i still have a p.o.s please help :)