Stumbles over 3,000 RPM

[Ger42]

I only changed the coolant and replaced the PCV valve.
2 weeks ago I changed plugs and wires. When I pull one of the wires off the coil doesn't seem to show as much spark as the others.
Yes I did them one at a time. Time for a new ignition coil?
Thanks
Gerry

 

[rurouni20xx]

thats a possibility, but let me ask you one thing, when you changed the wires did you put dielectric grease in the plug/coil connection and on the plug/wire connection? did the new wires come w/ this in them already? (like mine did...) if so excess grease can actually insulate the spark and make it go everywhere throwing ignition timing off and even prohibit proper spark. my trk did this when i changed the wires, they had grease in the boots and i didnt think anything of it, then it wouldnt start. i said well hell it may be that damn grease. wiped the grease out and she fired right up. another thing that may affect it, is your battery completely charged? if you have a crap or low battery the system voltage may be too low and actually cause a misfire. corrosion on battery cables and weak alternator/belt slippage cause similar problems. just a few little things i would consider.

 

[Ger42]

replaced ignition coil. Did not use grease on plug wires. I think it's a vacuum leak in the hoses from the cobbed up job the pervious owner did. I'll try spraying some WD40 around the area and se what happens.

 

[rurouni20xx]

try spraying carb cleaner around the intake gaskets and throttlebody area to look for air leaks, vacuum leak is also plausible. have you had your computer checked for codes?

 

[Ger42]

Possible it's a broken plug wire?
If I mixed up a plug wire would the truck even run?
Anyone have the wiring diagram for the plug wires?

 

[Beef52751]

my truck backfired like crazy and stumbled like you described when i mixed up a couple of plug wires.
Beef

 

[Bob Ayers]

The cylinder numbers should be on the coilpack. And passenger's side, front to back are cylinders 1, 2, 3, driver's side, front to back are 4, 5, 6. What kind of plugs did you use when you replaced them?

 

[Ger42]

The cylinder numbers should be on the coilpack. And passenger's side, front to back are cylinders 1, 2, 3, driver's side, front to back are 4, 5, 6. What kind of plugs did you use when you replaced them?

[/IMG]

This wrong?

I assume the coil pack is to the left. It has drivers side 5 6 4 from front. I've seen this in more than one place.
Plugs were Motorcraft.

 

[Bob Ayers]

[/IMG]

This wrong?

I assume the coil pack is to the left. It has drivers side 5 6 4 from front. I've seen this in more than one place.
Plugs were Motorcraft.

The coilpack isn't layed out like the cylinders are. Driver's side IS 4, 5, 6, front to back.

 

[Ger42]

Thanks for all the help. Still haven't found the problem. It is drivable doesn't seem to have a problem driving it easy. I have the problem revving it up in neutral. May try to get into it today and see what it does under load.

 

[rurouni20xx]

pickup coil problem under load? have you checked the fuel filter and fuel pressure? any codes at all? do you have an oil type filter and possible too much oil on it and messed up the maf?

 

[Ger42]

no oil type filter
no codes
I'll check fuel filter if I can find it
ignition coil is new no mile on it.

 

[rurouni20xx]

pickup coil gerry, the part on the engine that takes the crank signal or cam signal and sends it to the ecu so ecu sends the signal to the coil saying "fire now." not sure which sensor does it on trks. on bikes its an excitor or pickup coil, senses crank position on the flywheel and sends a signal to the ecm, then the computer sees where the crank etc is and sends the signal to the coil and the coil charges/discharges at the proper time making the plug spark. w/o the proper signal or signal at the right time the computer causes misfiring.

 

[Ger42]

pickup coil gerry, the part on the engine that takes the crank signal or cam signal and sends it to the ecu so ecu sends the signal to the coil saying "fire now." not sure which sensor does it on trks. on bikes its an excitor or pickup coil, senses crank position on the flywheel and sends a signal to the ecm, then the computer sees where the crank etc is and sends the signal to the coil and the coil charges/discharges at the proper time making the plug spark. w/o the proper signal or signal at the right time the computer causes misfiring.

Had Ford dealer replace that 2 weeks ago along with the shaft.

 

[rurouni20xx]

oh okay...lol