Cylinder 1 misfire

[Ace Ford]

Howdy y'all. I'm at my wits end (which is a short trip) and hope you might help. I recently bought a 99 Jeep tj, high mileage, 6 cylinder and I've been patiently "fixing it up". One problem quickly eluded me and unfortunately seems to be eluding my mechanic (who is really pretty darn good). So, here's the deal.

Almost every time I run it I get a cylinder 1 misfire. So far, I put in new injectors, full tune up, and new coil. Earlier, it idled very roughly until warmed up but that seems ok now. It actually runs relatively smoothly but doesn't seem to have the usual 6 cyl power I remember from my jeeps years ago. In 5th gear (it is a manual of course!) even on relatively level road at about 55 mph or so if you hit the accelerator hard pretty much nothing happens--super slow to accelerate and with much of a hill will not run the old 70-80 mph uphill I remember. Any ideas would be greatly appreciated. Thanks, Ace.

 

[djorgenson]

same on my 2002, msifire on #1, ran fine until recently, read numerous comments on # misfire for hot injector, does anyone think #1 injector has heat soak also?

 

[Jerry Bransford]

Howdy y'all. I'm at my wits end (which is a short trip) and hope you might help. I recently bought a 99 Jeep tj, high mileage, 6 cylinder and I've been patiently "fixing it up". One problem quickly eluded me and unfortunately seems to be eluding my mechanic (who is really pretty darn good). So, here's the deal.

Almost every time I run it I get a cylinder 1 misfire. So far, I put in new injectors, full tune up, and new coil. Earlier, it idled very roughly until warmed up but that seems ok now. It actually runs relatively smoothly but doesn't seem to have the usual 6 cyl power I remember from my jeeps years ago. In 5th gear (it is a manual of course!) even on relatively level road at about 55 mph or so if you hit the accelerator hard pretty much nothing happens--super slow to accelerate and with much of a hill will not run the old 70-80 mph uphill I remember. Any ideas would be greatly appreciated. Thanks, Ace.

Not much will happen if you hit the accelerator pedal "pretty hard" while you're still in 5th gear which is strictly an Overdrive ratio. Try downshifting to 4th when you need to speed up a little.

Also, what size tires are you running and what gear ratio is inside your axles?
There's a steel tag bolted onto the differential covers at their 9 o'clock position that has the axle ratio embossed into them. Depending on which axle you look at it'll say either 3.07 or 3.08, or 3.73 or 3.74.

This one is indicating the gearing inside is 3.73.

 

[Ace Ford]

Thank you sir and first a "duh on my part" on 5th gear--silly me, my old jeeps were 4 speed and without the overdrive. That makes sense. My tires are 32 X11.50R15 and I'll take a look at gear ratio and post soon.

Again, thank you for the response.

Ace

Not much will happen if you hit the accelerator pedal "pretty hard" while you're still in 5th gear which is strictly an Overdrive ratio. Try downshifting to 4th when you need to speed up a little.

Also, what size tires are you running and what gear ratio is inside your axles?
There's a steel tag bolted onto the differential covers at their 9 o'clock position that has the axle ratio embossed into them. Depending on which axle you look at it'll say either 3.07 or 3.08, or 3.73 or 3.74.

This one is indicating the gearing inside is 3.73.

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