This is topic intermittent miss help(new info!) in forum Tech Talk at Northern California Ford Owners  .


To visit this topic, use this URL:
https://californiafords.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=024131
Posted by 87redgt (Member # 9176) on :
 
I just recently built a 306 for my 87 gt. its been converted to mass air, has a trickflow stage 1 cam, 24lb injectors, gt40 heads, gt40 upper and lower intake, and a cobra mass air meter.
my problem is that it has an intermittent miss. its almost as if its firing in the wrong order, it happens very randomly. one day i could drive the car for an hour without any problems and then it'll miss really bad causing it to bog and sometimes slow down for up to a minute then it'll suddenly go back and drive like normal. then the next day it'll miss more than running right. it doesnt have a pattern to it or anything it just randomly does it on and off.
it has new spark plugs and wires, cap and rotor, and the distributor and coil are both a year old.
Any ideas on what it could be?

[ March 22, 2011, 07:36 PM: Message edited by: 87redgt ]
 
Posted by nasty93 (Member # 8935) on :
 
if it was my ride id check codes,check timing with a light,check for vacuum leaks,proper fuel pressure,clean mass air meter and double check all wires n plugs.just my two cents..
 
Posted by 87redgt (Member # 9176) on :
 
The mass air is brand new. I pulled the codes and these are what I got: 15,23,67,10,29,41,66,91.
 
Posted by x42bnx (Member # 9529) on :
 
It sounds like a MAF problem, new doesn't always mean good!
 
Posted by 87redgt (Member # 9176) on :
 
its been doing it a lot more often now, to the point of not being able to drive it. its also popping through the intake and backfiring. does this sound like it could be an o2 sensor issue? i've had the car for 3 years and they've never been replaced.
 
Posted by 87redgt (Member # 9176) on :
 
its been doing it a lot more often now, to the point of not being able to drive it. its also popping through the intake and backfiring. does this sound like it could be an o2 sensor issue? i've had the car for 3 years and they've never been replaced.
 
Posted by nasty93 (Member # 8935) on :
 
double check your timing with a light
 
Posted by 87redgt (Member # 9176) on :
 
quote:
Originally posted by nasty93:
double check your timing with a light
yeah its still at 14 degrees. its just weird because it started only missing a couple times per drive and it progressively got worse to where now its not driveable
 
Posted by 87redgt (Member # 9176) on :
 
tried to work a little on it today. its not the o2's. now if its out of gear and i give it full throttle it'll pop through the intake once then rev up. when it gets to around 1500rpms it'll sputter and cut out a little throughout the rest of the rpms.
 
Posted by tribal3579warrior (Member # 5663) on :
 
Check your mass air sensor, wires and ECU. What year wiring harness did you use? What year is the ECU from?
 
Posted by 94 N.C.F. GT (Member # 3946) on :
 
Mine does the same thing everyones in a while [Confused]
 
Posted by 94 N.C.F. GT (Member # 3946) on :
 
Any update
 
Posted by Secnd2nun64 (Member # 1431) on :
 
I would think it would be a vacuum leak based on what your talking about. It would be a good idea to change out all the vacuum lines if they are original.
 
Posted by 87redgt (Member # 9176) on :
 
no idea what year the wiring harness was from, it was converted to mass air before i got it and all the hoses are fine. it was okay before i put the 306 in. it sat for about 4 months during the process. basically re-used everything from the 302 with the exception of a new mass air meter. it ran fine for about 50-100 miles before it gradually started getting worse to the point of it not being driveable. it does it with the mass air unplugged also. i gave up on it for now, it was getting to frustrating lol.i don't even know where to start.
 
Posted by CHP2981 (Member # 9240) on :
 
Someone else has similar problem. When I did my conversion in my 87 I forgot to change the MAP sensor from the speed density, it still plugged in but you have to use the mass air one and block off the intake side with one of those rubber plugs. It still ran but I had all kinds of backfiring it's been a wile sense I fixed it but if you still have a vac hose coming from it, it's not the correct one. Hope I helped you.
 
Posted by 94 N.C.F. GT (Member # 3946) on :
 
did a lil reading and it could be a bad map sensor and there free at pick n pull [Wink]
 
Posted by x42bnx (Member # 9529) on :
 
Actually, please check ignition coil. I went through trials and tribulations diagnosing mine, it was ignition coil.
 




Fueled by Ford Mustang Owners
on CaliforniaFords.com