94 4.0L misfires like out of time?

[zaathur151]

Have a 94 4.0L with 125,000, it misfires so bad it will not stay running will buck bad and pops through the intake has new plugs wires and coil pack double checked the firing order twice no check engine codes any ideas

 

[Anime]

Probably wrong firing order on the coil pack, especially if it's aftermarket. The stock coil and the aftermarket coils don't have the same wire arrangement.

Cheap wires and/or cheap plugs will affect ignition too. Same for plug gap.

 

[zaathur151]

i have autolight platinums in it so there pre gaped and how do i tell if the coil pack is different it take from oreillys

 

[zaathur151]

ok i changed out the mass air flow sensor and it will run and idle now but still misfires bad and has zero power i changed the spark plugs again because they looked fouled still no improvment

 

[MrShorty]

Was the misfire present before changing the plugs/wires or did the misfire develop after?

 

[zaathur151]

drove to get a inspection ran perfect on the way home from that it started missing did a normal tuneup still nothing then coil pack and fuel filter and mass air flow sensor that did help but still misses

 

[MrShorty]

So the misfire developed on its own, not in response to anything replaced.

Can we assume that, when you say the computer gave no codes that you mean it gave all pass codes?

I would probably put a fuel pressure gauge on it to see if the fuel system is doing what it should. I might also try a cylinder balance test to see if the misfire seems isolated to one or two cylinders, or if it occurs on all cylinders equally.