Help! Truck misfiring, need to do 300 mile journey in 4 days

[rigby]

Hey Rangerstation gang!

My truck (1995 2.3L standard cab, 5 speed, 256,000) has been juddering or misfiring for a while but its gotten worse and worse recently. The whole car shakes, like its been switched off and on again suddenly. No sound that I've heard as a result of it. No tach so I cant say what the RPMs are doing. It doesn't sound like its idling all that rough.

First showed up during the winter on a wet night, figured it was electrics, it was fine the next day. Changed the air filter just for kicks.

Didn't have a problem for a while after, drove it from Ithaca to NYC and back just fine.

Then it started juddering more and more, right now it runs fine for the first 10 or so minutes then the problem snowballs to the point where its almost un-drivable. I've got to move out of my house in the next few days and drive to Maryland and I'm on a bit of a budget.

I've changed plugs (champion) and wires (napa) the old ones were very corroded (plenty of rust and dirt), and fuel filter. This certainly gave it more guts but the problem still persists.

My dad's coming up this weekend to help try and get it running okay enough to do the 300 mile journey to MD, anyone have any pointers of what item to attack first?

I'm thinking fuel pump. Or maybe the Cat'....

 

[v8318cid]

Check your coil pack(s). Could be failing once they reach operating temperature. Won't always throw a code and will sometimes give little indication at idle that there is a problem unless you goose the throttle (bogging down at first before revving up).

 

[97ranger xlt]

clean your maf

 

[rigby]

Hmmmm, there has been a little indication at idle since it really started doing it. Doesn't idle "rough" but the rpms will dip for a second every once in a while....

The internet tells me to resistance between the contact and the plug for the pack should be between 0.3 and 1.0 ohms?

 

[rigby]

Okay, Primary resistance is 0.7ohm on middle to outer pins, and the two outside pins are 1.2

Secondary resistance is 13K across the board.

Identical on both the units. Are these in range or way out? All these tests were done cold, so like you said since its only an issue once it gets up to temp might not actually indicate anything.

 

[modelageek]

Okay, Primary resistance is 0.7ohm on middle to outer pins, and the two outside pins are 1.2

Secondary resistance is 13K across the board.

Identical on both the units. Are these in range or way out? All these tests were done cold, so like you said since its only an issue once it gets up to temp might not actually indicate anything.

the resistance readings are fine but the coil could still be bad.....swap the coils and if the truck runs differently then it is a coil. if that was my truck I would do fuel pressure tests on it and I also would also check for pending codes when the truck is acting up........

 

[Bryan22]

Sounds like the coil packs are fine. first thing i would do is put some autolite or motocraft plugs in it. I chased a similar problem for a year before changing the plugs to find out bosch plugs were the problem the whole time. no codes or anything.

Besides that I would say get some fuel pressure readings from the rail as model a suggested, and let us know what's goin on there.

 

[modelageek]

Sounds like the coil packs are fine. first thing i would do is put some autolite or motocraft plugs in it. I chased a similar problem for a year before changing the plugs to find out bosch plugs were the problem the whole time. no codes or anything.

Besides that I would say get some fuel pressure readings from the rail as model a suggested, and let us know what's goin on there.

I agree with using only MC or autolite plugs......however since it sounds like the issue was there before and after the plug swap that is probably not the issue.......I just recently had a ford Focus coil pack that tested fine with a MM but had a spark issue on the #4 cyl.......it ended up being the coilpack......I solve many issues by randomly checking for codes and getting a pending code.........I have a $20 codekey reader..........PRICELESS

If you never get a pending or full code it could very well be a fuel issue.....

 

[rigby]

Swapped the coils, that smoothed it out it to the point where it made the journey just fine and I'm back and safe.

At crusing speed on the highway she's fine. But it still does a little bit of juddering going up steep hills in too high a gear (under 30 in 3rd under 40 in 4th etc)
And for some bizarre reason when i switch on the turn signals/headlights it does it once....

Oh well. Its in my dads hands now.