Cylinder 3 is continually misfiring. Any ideas?

[TonkaMan]

The third cylinder in my 97' ranger is misfiring and I can't figure out why. I took it in to a shop and they spent 5 hours working on it. They said a fuel injector was clogged and the engine computer was malfunctioning and not sending a signal to the third cylinder to fire. They replaced the engine computer and the fuel injector, a $500 job just in parts. The check engine light didn't come back on for 2 weeks, but then it came back on with the same problem. I also replace one ignition coil and all of the ignition wires. I was wondering if anyone on here was having a similar problem or would know how to fix it.

 

[scotts90ranger]

did you change the spark plugs? a cracked spark plug will cause the same problem

 

[TonkaMan]

that was one of the first things we thought of. And also I'm pretty sure that after the 5 hours of checking things at the shop that would have gotten checked.

 

[bcost882]

not always. how bout the spark plug wires?

 

[scotts90ranger]

he said they replaced them, that's why I didn't mention it...

 

[BogusSVO]

cracked exh seat and/or burnt valve... do a compression test ir leak down test

 

[TonkaMan]

the compression test checked out fine

 

[BRUTUS_T_HOG]

the first thing i can tell you is that you had no reason to buy a new computer... why?

because when the computer detects a misfire it shuts off the signal to that injector to reduce emissions, thats why the shop couldn't find a signal.

tell them about that and see what they say, ask them why they did not know this

 

[chazzone]

I'd recheck that plug, and the spark gap. It doesn't matter if they did or didn't. Its simple, and could be the issue. I've had brand new plugs go bad right out of the box (in fact just had three go bad on the son's BMW that I replaced this past summer).

 

[modelageek]

The third cylinder in my 97' ranger is misfiring and I can't figure out why. I took it in to a shop and they spent 5 hours working on it. They said a fuel injector was clogged and the engine computer was malfunctioning and not sending a signal to the third cylinder to fire. They replaced the engine computer and the fuel injector, a $500 job just in parts. The check engine light didn't come back on for 2 weeks, but then it came back on with the same problem. I also replace one ignition coil and all of the ignition wires. I was wondering if anyone on here was having a similar problem or would know how to fix it.

I doubt this is what your issue is. yours sounds a little more complicated, however I developed a misfire on my 4 banger cyl 3. code p0303. it was an extremely clogged fuel filter.

you also could swap the coils and see if the issue gets a little better or a little worse.if this happens it is the coil pack.

 

[Bryan22]

glad u figured out your problem model A! hope you didn't throw too much money at it. haha.

anyways, one thing i would try is going somewhere very dark and open the hood while the motor is running and look for sparks. if you see some spark leaking you know where to start looking. i've had a brand new set of plug wires leak all over the place, truck ran like crap.