Aaaarrrrggghhhhh missing issue

[Rokkit]

ok so im having issues.. what i have is a 07 gt tuned by bama with udp's mac long tubes with prochamber twin 62 gms throttle body air raid cai and it has developed a miss. the car has 85k miles on it and i believe that it still has stock plugs and COPs i say this because i purchased the car in feb of 2014 without in stock form. i would like to know what other people think. the car doesnt miss in first or second gear under hard acceleration or heavy load but once im in third gear around 5k rpm its starts to miss and you can hear it backfire and pop and it seems as if when its under this heavy load before it starts missing that its not pulling as hard as it was in first and second gear. it will miss in 3rd and if i shift while its missing in 3rd to 4th it will continue to miss and even while cruising in 5th around 90 mph. im baffled seeing as ive done multiple datalogs and bama says the car is doing everything that they are telling it to do.. all help will be greatly appreciated im really wondering what some of you think. if i can find a video soon i will upload

 

[JeremyH]

About time for new spark plugs anyway, pull the plugs and start there.

 

[BruceH]

ok so im having issues.. what i have is a 07 gt tuned by bama with udp's mac long tubes with prochamber twin 62 gms throttle body air raid cai and it has developed a miss. the car has 85k miles on it and i believe that it still has stock plugs and COPs i say this because i purchased the car in feb of 2014 without in stock form. i would like to know what other people think. the car doesnt miss in first or second gear under hard acceleration or heavy load but once im in third gear around 5k rpm its starts to miss and you can hear it backfire and pop and it seems as if when its under this heavy load before it starts missing that its not pulling as hard as it was in first and second gear. it will miss in 3rd and if i shift while its missing in 3rd to 4th it will continue to miss and even while cruising in 5th around 90 mph. im baffled seeing as ive done multiple datalogs and bama says the car is doing everything that they are telling it to do.. all help will be greatly appreciated im really wondering what some of you think. if i can find a video soon i will upload

About time for new spark plugs anyway, pull the plugs and start there.

This^^^. No matter what they say about 100k spark plugs don't go that far on them. Especially if you are beating on the car. Get some stock plugs and change them. You should do all the regular stuff if you haven't already like cleaning the maf.

 

[Rokkit]

will do was going to be changing them in the near future seeing as i will be adding nitrous when the weather warms back up around here. but i guess what through me off was the fact that it never missed or had this prob before adding the long tubes and twin 62 throttle body so i was thinking that it could possibly have been the tune. what do you know about the cops breaking down or who has experienced this?

 

[skwerl]

Could be lots of things but it's a waste of time to speculate without checking the basics first.

 

[Rokkit]

mk so back to working on this issue.. cars been pulled out of storage spark plugs changed (which turned out to be a total pain) and coil swapped. new ford 0degree plugs and accell coils and shes still missing like crazy in mid to high rpm with a heavy load.. will be pulling the plugs today and checking them after this comes a compression and leak down test. anyone have probs with stock fuel injectors??

 

[skwerl]

Make sure all the electrical connectors are attached to the injectors and fully engaged. The locking tabs tend to break and then the connectors get loose. If you have any broken locking tabs then you want to use a small zip tie and secure the connectors so they are fully engaged.

 

[rocky61201]

Also check to see that the new plugs you put in don't have any porcelain broke that slip down to the ground strap and cover up the electrode. It can happen if you drop them on accident. It did to me. If broken the porcelain will float or move up and down over the electrode causing the intermittent misfire. Pull the plugs and shake them to see if any are broken.

 

[AnotherS197GT]

What coil packs?

 

[Rokkit]

Accel coil packs and ford racing 0 degree plugs... was getting her ready for nitrous.. but if i cant get rid of the miss she will never see it...

 

[Rokkit]

will be checkin plugs today after work... anyone know how to test the coil packs and injectors with dvom to make sure they are working?

 

[AnotherS197GT]

Did you try new plugs with stock coils? Aftermarket are notoriously crummy. What are the plugs gapped to?

 

[Hawgman]

Not saying that this is your issue, just something to consider.
I chased a miss for a while, and it was a specific scenario type of miss. Turned out to be a damn injector.

 

[JeremyH]

I would put stock cops back in, check plug gap and replace fuel filter and reload the tune, has it always done it since you got the car? It can be an injector as well but not as likely.

 

[Rokkit]

no i didnt try new plugs with old coils and as far as the gap from what i read they were preset and couldnt be gapped.. but i could be wrong.. fuel filter was changed and i didnt notice it until i installed my mac long tubes pro chamber and twin 62 gms throttle body... have datalogged and when i sent them in they say the car is acting as it should and that they cant see a missfire and have received a few tunes with no change..

 

[Rokkit]

but i will say even b4 the headers and throttle body that even having 3.73s i felt the car has always been sluggish in 3rd and 4th gear which was making want to step up to 4.10 but i could have been having the miss the whole time just wasnt as noticeable because the car wasnt breathing as good ya know.

 

[JeremyH]

Always always check and set the gap yourself, even if it says pre-gapped. Who knows what they are at and if they are all the same.

 

[Rokkit]

gonna pull and check em all here in the next hr or so.. and lemme guess there is a special triton tool for that... lol

 

[Rokkit]

and what should the gap be set @ if u dnt mind me asking

 

[JeremyH]

You can check gap with feeler gauges. And there is a tool that makes it easy buts its not absolutely necessary. Depends on the setup. Na around .044, tighter for boost or nitrous.