Hello fellow ford people. i've got an 88 f150 that i just pulled the 302 out of and put a 351 in. i'll add i don't have the exhuast on it yet but i've got a slight problem. when your going down the road in 3rd4thor5th it seems like the truck has no power at all and it misses. i used all the 302 wiring and put a 351 dist and ecm in it. thought it might be in the dist so i put the shaft outta the 351 in my 302 dist and it's still the same other than seems like it responds better off of idle. there is no vacuum leaks. tps is new. could the 302 map sensor cause this. i might add i used the 302 air temp sensor and water temp but wouldn't have thought those would make a difference. any help will be greatly appreciated.

 

No exhaust means no O2 sensor right? Is the EGR on the motor? There are no engine specific sensors they are all the same for both motors so they aren't causing any problems unless they are bad. Get some kind of exhaust on it and the O2 hooked up and then pull the codes.

 

that's what i'm waiting on now. i had it done by one guy and he didn't do a very good job. so now i got it to another shop and he's gonna cut it out ang redo it.

 

conanski, i've been reading some threads with symptoms similar to mine and it's something to do with cross firing plug wires?(meaning they are wired right but will fire in the wrong pattern cause they are too close to one another?) i'm fixing to go pull some codes after i retighen my exhuast up cause this dude that done the work for me yesterday did a good job except his bras nuts weren't tight enough and i have already lost one

 

Yes make sure the wires are seperated as much as possible, on the 5.8 cylinders 5 and 6 are right next to each other in the firing order and are most likely to cause problems if they crossfire.

 

ok i pulled the codes. and i hadn't done it since i'd hacked the harness for carb. so i ended up with some false codes. the hego code, egr, fuel pumps, air intake sensor, ac sensor. cleared the codes and rerun a test after starting it up and letting it run. came back with egr an ac codes and none on continuous memory. i gotta get a stud for the exhaust and he didn't put my o2 sensor back in so not sure what to do about that. but i made sure the wires are farther apart. none where criss crossed but touching. if i pull the spout connector and the miss goes away what direction should i go?