misfires woooot

[GP99GT]

k i know this isnt the "correct" forum to be asking mustang questions on, but i posted on corral.net and got no response. i seem to have an intermittent misfire. drove it around today after changing my last spark plug, ran fine, raced an srt-4, yadda yadda. parked it at my cousins for maybe 45 mins, got in it to go home, pull out...first gear fine....2nd gear the car starts missing, sputtering, tach keeps dropping down every time it does it, and it did it the whole way home. it was also doing that yesterday, i thought maybe it was that last plug i didnt get to change, but thats obviously not the case. it was doing this before i did the plugs/wires too so its not related to that. has new plugs/wires/cap/rotor, fuel filter, recently ran some injector cleaner through it, cleaned the TB out, so the basics are done. any ideas? its an 87 5.0 with speed density. Ian suggested the MAP sensor, im also thinking coil or ignition module on the distributor.

[IROCdan330]

if i recall intermittent MAP issues arent all that uncommon in fords. The only way to know for sure instead of guessing would be a scan tool (make a movie of the pid data). How much are they to replace?

[GP99GT]

its like $60 or so my cost at the parts store i work at. i might be able to just pull it off the shelf and put it in and try it out, if it still does it i can just box it back up :lol:

[GP99GT]

Tried a new MAP sensor, didnt work. Gonna try a coil now, any other ideas?

[foff667]

should I put in the obligatory "Yeah I got an idea buy a GM" comment now? lol sorry I had to...as for your question I honestly have no clue...you've replaced all of the ignition components other then the distributor itself :shrug:

[GP99GT]

well i took the old coil off, on the fords theres a metal ring that goes aroundt he outside that grounds it...that ring was kinda loose and flopping around. threw on the new coil, so far so good...havent driven it much yet so we'll see.

[GP99GT]

annnnnd it just did it again last night. sigh

[maroman88]

just steal parts off shanes car lol

[Savage_Messiah]

k i know this isnt the "correct" forum to be asking mustang questions on, but i posted on corral.net and got no response. i seem to have a ford

sorry to hear

[GP99GT]

well this morning i got in the car and it wouldnt start...connection for the ground on the block was all ****ted up. maybe thats why my ignition was having problems? who the F knows

[foff667]

go ford! Then again the car is 20 years old now so I guess its one of those "what do you expect" kinda deals...hopefully that was the fix.

[WildBillyT]

well this morning i got in the car and it wouldnt start...connection for the ground on the block was all ****ted up. maybe thats why my ignition was having problems? who the F knows

Hell yeah it could be your problem! :shock:

Just for reference, MSD units are known for having intermittent problems if they are improperly grounded.

[Batman]

I don't know much about fords but does it have any sensors int he TB? if you cleaned it with the sensors in you might have jacked them up. Does it idle OK? Does it stumble at part throttle? You may have a timing chain issue also. Did you pull the distributor when you did the plugs/wires and maybe install it 1 tooth off?

[foff667]

I believe they have the tsp & iac sensors in the TB if im not mistaken.

[GP99GT]

yeah, theres the TPS and the IAC...no MAF cause its speed density. fixing that ground didnt help, it did it again yesterday...then a few hours later my alternator decided to die....lmao

[IROCdan330]

The way I would approach it, as it is intermittent, would be to plug the scan tool in and go out for a drive...when it does it, hit record...then bring it back, and review your data. The scan tool will record before you push the button...so find your miss, and see what looks f-ed up on the scan tool. That should lead you in the right direction...if you have a scan tool.

[GP99GT]

i dont have a scan tool, but my uncle does. he has all the fun snap-on stuff. it hasnt done it recently though...stupid ford

[best of both]

Pull the dist cap off, If the pickup is black or there is oul on the ickup it is probably cracked. The black ones were used from the factory until around 89 when the white pickups were installed. Also you want to make sure when the speed density conversion was done the wire were soldered not installed with the snap lock connections, if you have a bad ground at the connection it will miss under load.