98 5.0 Slight miss at low RPM, started buckiing/stalling this morning

[Mbrooks420]

My 98 Mounty v8 has had a slight miss at low RPM's for some time. Never anything major, happened almost always right around 40mph at minimal throttle, right before it was time to downshift.

A few moths ago it bucked like it wasn't getting either fuel or spark 3 times in a a 5 or so second span. That week it also had a time it wouldn't start. Turned over for 6-8 seconds. Then I turned the key off, waited a few seconds, turned the jkey and it started right up. After that no probs but the slight miss.

This morning it started bucking again. Did it maybe 10 times in a 20 mile drive on the highway. Mostly lower RPM. I turned the OD off so it would run at a higher RPM, and shortly after turning the OD off it would turn the OD light off, and shift into overdrive.

Where do I begin? I have new wires, so I am going to put those on. I don't expect that to fix it, but they are horrendously overdue. Truck has 170k and they are stock Going to check the fuel pressure at the rail. Going to search on here how to test the coil packs.

Anything else I should be testing right off the bat? Right now I am betting on fuel pump, or coil pack. The OD turning itself on worries me. Does the torque converter clutch failure trigger the od light to blink?

 

[Turdle]

Hi Mike
Try the new spark plug wires, see if that will whip it into submission

That would be my first step. New plugs also. You may have a cracked one.

If there is an electrical arcing to ground it may cause all kinds of issues.

 

[Mbrooks420]

The plugs are less than 10k old, but I might as well yank them when doing the wires, they are cheap enough.

 

[Mbrooks420]

Only did it once on the way home, drove longer than normal. Another thing came to mind. My filler neck seeps a bit of gas when I fill up. I assume if gas can seep out, water can seep in. Going to have to fix that as well.

 

[scottdbutcher]

I had a similar problem recently on my 1996 5.0. I replaced the plugs, wires, seafoamed the engine, on and on and nothing fixed it. Just a light skip, mostly @ idle. Turns out friday, truck died, needed a fuel pump. After a tow home, $140 for fuel pump, and 4 hours of wrestling with a 22 gallon tank 3/4 full (lol) i changed the fuel pump, and now there is NO skipping or anything. Runs better and seems to have more power as well. This was all at about 184,000. That may be your problem........ run the tank empty if you want to change it!

 

[Mbrooks420]

I am thinking the fuel pump is the most likely. I dropped the tank once because of a leak. Not too terrible of a job. Actually considered cutting a hole in the floor like others on here have done, given the temperature of my garage floor.

 

[2000StreetRod]

Change fuel filter

I suspect that many fuel pumps fail prematurely because the fuel filter isn't changed regularly. I suggest that you change the filter and then add a bottle of fuel injector cleaner to the tank. If you're definitely going to replace the pump, do it before you replace the filter. Then add the cleaner.

 

[Mbrooks420]

Its definitely due for a filter change. I need to pick up a set of pliers for those clips.

 

[scottdbutcher]

Yeah get a good set of pliers, when i did it, it was 10:00 at night and i needed the truck the next day, so i beat the lines off with a screwdriver and hammer. It was a disaster, but i was able to fix the clips and use them......i thought about cutting a hole in the floor, but its right below where my 2 year old daughter sits, so i dropped the tank instead. Good luck!

 

[ViperPliskin]

Bucking

Ever find out what was causing your problem?

Did you check fuel pressure? I have a similar problem...checked my fuel pressure and it was running high...60 PSI. Thought it might be a vacuum issue.