2000 ranger spark plugs PLEASE HELP!

[Clarissa]

I just bought my truck about 6 months ago, immediately I had to get my plugs and wires changed, my truck was progressively getting worse and jerking really badly when accelerating. My plugs we messed up again with I two weeks, they finally figured out that the thermostat was stuck open causin the spark plugs to go bad almost immediately. After fixing that it ran like a champ for about 5 months and now is beginning to do the same thing. It starts sting, but very rough. It takes about 10 seconds to even out and run smoothly. Any suggestions to what could be causing this? I know of a couple people who have to change out plugs on their rangers every few months.

2000 ranger v6 4.0 4x4

 

[shane96ranger]

It takes about 10 seconds to even out and run smoothly.

This is also a symptom of a leaky fuel pressure regulator. After you run it for a few minutes, pull the vacuum line off the fuel pressure regulator. Wait and watch it for a few minutes and see if it starts leaking fuel out of it.

 

[straycat]

If you are not sure as what to do take it to a local honest shop and have them run a diagnostic on it. This will stop wasting your time and it won't nickle and dime you to death.

 

[Clarissa]

I had diagnostics testing done 3 diff times, they all said "misfire on cylinder 4" and one place tried to tell me that I had a blown head, which is not true. After that I took it to an honest person that I know which is when the wires and plugs got changed. Then two weeks later same problem and they put in a new thermostat and changed the plugs again. Which lasted for 5 months.

 

[shane96ranger]

I had diagnostics testing done 3 diff times, they all said "misfire on cylinder 4" and one place tried to tell me that I had a blown head, which is not true. After that I took it to an honest person that I know which is when the wires and plugs got changed. Then two weeks later same problem and they put in a new thermostat and changed the plugs again. Which lasted for 5 months.

OK, by cylinder 4 (drivers side all the way in the front), does your valve cover gasket leak oil and get to the plug? Oil can crack the plugs. I know from experience (even the same cylinder 4).

 

[Clarissa]

There is no oil leaks at all, it has never dropped ANY oil.

 

[shane96ranger]

There is no oil leaks at all, it has never dropped ANY oil.

I didn't think mine was either. There's a lot of crap right there, at least there was on a 96. It's difficult to see.

What plugs are you using?

 

[Clarissa]

I'm not sure what kind.

 

[adsm08]

You have done plugs and wires ad naseum it would seem. Have you ever changed the coil pack?

If you want a cheap and dirty test for the coil pack swap the plug wires for #4 and the one directly across the coil from it, see if the miss moves to the paired cylinder.

 

[Clarissa]

They did the ignition coil as well, 5 months ago.

 

[shane96ranger]

A cylinder 4 misfire could also be a fuel injector. Have you explored that avenue?

 

[adsm08]

A bad injector wouldn't foul plugs without causing other issues.

 

[Clarissa]

Fuel pressure regulator did not leak when vacuum was removed. Spark plug not cracked, looks brand new, clean. Valve cover leaks very little oil, not even close to plug 4. Fuel pump working properly. Fuel filer recently replaced, good compression.

 

[Clarissa]

Had my brother look it over, he checked all these things

This is also a symptom of a leaky fuel pressure regulator. After you run it for a few minutes, pull the vacuum line off the fuel pressure regulator. Wait and watch it for a few minutes and see if it starts leaking fuel out of it.

Fuel pressure regulator did not leak when vacuum was removed. Spark plug not cracked, looks brand new, clean. Valve cover leaks very little oil, not even close to plug 4. Fuel pump working properly. Fuel filer recently replaced, good compression.