Please HELP!!VERY BAD Misfire/fuel cutout problem

[4valvemach]

I know this is the COBRA section but please help a brother out if you can :beer:

2004 Mach 1
5spd
118k miles
ONLY mods JLT intake and welded in flowmasters
FUEL MILEAGE IS NOT HURT WITH THIS PROBLEM STILL GETs 290-315 per tank as it did when I got the car at 26k miles

The problem I have is the car has a misfire/fuel cut out symtom that starts at 2800rpm and goes till redline.Its as if the engine stops and then goes when going through the rpm's

example(each rpm listed would be a stop point in the rpm's when trying to accelerate)

idle....28k...31k.....35k....37k....41k.....43k...48k..50k...53k...56k....etc etc

With the engine running you can watch it have a not normal more of a erratic shake to it.Ive had it on two scanners about five times with no codes showing.The fuel pump died about 1500 miles ago and was replaced with a OE pump.The problem I have now is/was the same before and after the pump install.The mis/cutout did go away for a few days after the new fuel pump was put in :shrug:.

NEW PARTS INSTALLED
fuel pump (walbro)
spark plugs (motorcraft gap at .54)
fuel filter (motorcraft)
front 02 sensors (NGK)

tested coils with volt meter (good)
checked for spark from all 8 coils(good)
"listened to injectors" they all sound the same
sprayed around intake lid for leaks, none found

 

[006]

Do you get a CE light at all?

Check for instrument dtcs and see what comes up.

Mustangworld HEC Instrument Cluster Diagnostics

 

[Bad99SVT]

If it is a aftermarket walbro i dont think it will last long...they are desgined for the return style systems and not the returnless...may be the pump is screwed up?:shrug:

 

[Black*Death]

I would close the gap on the spark plugs a bit. I think Walboro finally made a pump for returnless system.

Need a tune for the JLT?

 

[4valvemach]

Do you get a CE light at all?

Check for instrument dtcs and see what comes up.

No CE light on ever not even after staying WOT till redline,I would think as bad as it is the CE light would come on!!The instrument DTC only shows a oil pressure switch inop code.

If it is a aftermarket walbro i dont think it will last long...they are desgined for the return style systems and not the returnless...may be the pump is screwed up?:shrug:

Would it not run period if it was the wrong style pump?

I would close the gap on the spark plugs a bit. I think Walboro finally made a pump for returnless system.

Need a tune for the JLT?

The JLT intake has been on for almost 40k miles and the gap per ford is .52 -.56:shrug:

You can give the car a good amount of gas and have no problem but put the pedal to the floor and its a problem.Alot of people have said "coils its the coils" even when the spark plugs show no sign of ignition problem.So today I picked up one new coil and swapped with one old one.I drove the car and went WOT and it cut out just like before.I put the old coil back in and pulled the next,did this for all the coils.So I would think I have rulled out the coils being bad or breaking up under load :shrug:

 

[99MystiC]

Ok while its idling, have you had some one pull off an injector and then listen for a diff in idle? Same thing with the coils? Pull one at a time and listen for a diff in the idle, to try to pin point where the miss fire is at. Ive also had a type of problem with a cutout when on the track and one problem ended up being was a kinked line in the tank. Is the fuel hat OE. Fuel line and everything? Still have the pprv in it?

 

[Black*Death]

I would still try and make sure the problem isn't the plugs? Unless you have pulled all of them checked for wear, damage, or worn out then I personally would not be content.

But I am not standing by your car trying to help so it is up to you

 

[4valvemach]

Ok while its idling, have you had some one pull off an injector and then listen for a diff in idle? Same thing with the coils? Pull one at a time and listen for a diff in the idle, to try to pin point where the miss fire is at. Ive also had a type of problem with a cutout when on the track and one problem ended up being was a kinked line in the tank. Is the fuel hat OE. Fuel line and everything? Still have the pprv in it?

I have pulled each coil one by one and it goes POP..POP....POP in the exhaust and runs even more rough.Ive always been told that the coil that does not effect the current idle is the bad one.I have not checked the injectors yet but will shortly.The Fuel HAT is the FUEL PUMP MODULE ASSEMBLY correct,yes its all still OE other than the pump.

I looked into the PPRV (its still in my car) and it seems more like a 03/04 cobra problem when shifting only :shrug:

I would still try and make sure the problem isn't the plugs? Unless you have pulled all of them checked for wear, damage, or worn out then I personally would not be content.

But I am not standing by your car trying to help so it is up to you

Im looking for any help man :beer:

Ive had the plugs out about 4-5 times since the new fuel pump and each time they still look new.

 

[4valvemach]

Ok so Black*Death got me thinking more about the spark plugs and today I pulled them all out.

3 had a out of the box NEW look
2 had a almost new look but with white/silver specs
3 had white/silver specs and a blackish tint to them

With ^^ those plugs the digital RPM was 676-718 and a very eratic idle

I went ahead and replaced the plugs today with NGK TR55IX spark plugs(gap .52).It has a much better idle not near as eratic as before digital RPM is now 699-715.

I test drove it only to have the same problem still!!!! But it idles better

Maybe I have more than one bad coil (?) kinda hard to believe and not get any codes:shrug:

 

[99MystiC]

Check the injectors, thats the other 50% that goes on in there . The only reason i asked about the pprv is that once it is deleted there is a chance for issues.

What would help out is if someone in the area can let you barrow coils and injectors. Just swap really quick and see if the problem goes away.

 

[Black*Death]

I have pulled each coil one by one and it goes POP..POP....POP in the exhaust and runs even more rough.Ive always been told that the coil that does not effect the current idle is the bad one.I have not checked the injectors yet but will shortly.The Fuel HAT is the FUEL PUMP MODULE ASSEMBLY correct,yes its all still OE other than the pump.

I looked into the PPRV (its still in my car) and it seems more like a 03/04 cobra problem when shifting only :shrug:



Im looking for any help man :beer:

Ive had the plugs out about 4-5 times since the new fuel pump and each time they still look new.

Cool...didn't realize that

 

[4valvemach]

Had some free time so I put the car on the scanner again today and cleared all learned memory.With playing around on it I came across "misfire count" so looking at that and reving it up about 7-8 times to 4-5krpm.

Total misfires = 714
Every time the RPM reached 3k and over the misfire count would go up.

Still no DTC in the computer:bash:

So Im going to just replace all the coils with ford racing ones:shrug: