Well, I have a stumper.

I've got a 98 Ranger 3.0L that's been a great truck, but I've had a problem over the last month or so.

The truck runs like a top most of the time, but every few days it'll start running badly, as if one (or more) cylinders isn't firing or getting fuel to it. It'll run like this for a couple of days, and then it'll go back to running smooth again.

I'm confused, because the intermittent nature of the problem makes me think it's something electrical....but I'm not sure what could be the problem given:

>> No Codes to indicate a sensor problem
>> New Plugs, wires, coil pack

So, I'm curious if one (or more) of the injectors isn't firing. The truck's got 170K miles on it, so I'm thinking maybe the injectors are clogged or otherwise malfunctioning.

Anybody have any thoughts? I know this isn't much information to work from, but I'm stumped.

Thanks in advance

Ryan

 

Did you replace the plugs, wires & coil before or after the problem started?

Have you tried testing the fuel pressure when it's running bad? Has the fuel filter been replaced?

 

From what you describe, I would also suspect injector(s). Does it sometimes run rough when first started? It could have a flooded cylinder if an injector sticks open. If it just starts running rough randomly it could be a lot of things. I'd run a couple of bottles of Chevron Techron concentrate through it and change the oil in case your getting fuel dilution.

 

Thanks,

I'll try the fuel filter and pressure.... the filter has been recently (last year or so) replaced, but I figure it's cheap to try it....I would think though that if the filter was plugged, then it'd be plugged pretty much continuously...not run great for a few days and then bad for a couple. I guess I could be wrong though.

And yes... I did change the plugs, wires, and coil after the problem started....didn't make a difference. Also ran one bottle of Techron through it....didn't make a difference.

I'm curious...what are my options as far as testing/cleaning the injectors? I'm still living in a world in which a $12 carb kit and a 1-bbl Carter was the answer to fuel delivery problems.

Thanks

Ryan

 

I think I am having a similar problem. I have a '99 XLT with a 4.0L. Over the last few months I get a rough idle once in awhile and randomly when driving I get a loss of power and it seems to be getting slightly worse. Sometimes when I hit the gas and it won't accelarate and runs rough and then finally kicks in. I have done nothing yet and was searching the forum to look for answers. I thought plugs and wires or some sort of fuel delivery. I replaced my fuel filter a lttle less than a year ago. The truck has 92,000 miles on it. The intermittent nature of this just has me a little confused and not sure what it is. Just though I would join in here..

 

You can have them cleaned at may auto repair shops. They have some stronger cleaner/fuel in a pressurized bottle, (similar to a propane torch tank I think..), that they connect to the fuel rails. They run the vehicle off of the bottle until it is empty.

There are also places you can send them into and have them individually cleaned and tested. Of course the vehicle will be out of service for a while.

 

This seems to be the same problem I posted about last week or so. Runs great for a while, then starts to miss or something especially when getting on it to get on the freeway or pass. Sometimes it wants to hesitate in the morning when I'm pulling away from the curb in front of the house. I'm changing the fuel filter in a few minutes. Sure hope that works for me.

 

I'd try having the computer checked for trouble codes, or pending codes.

If that doesn't offer up any clues, I'd check the throttle position sensors electrical connector to be sure it's properly fastened, pins & sockets & wires, for damage, looseness, bent, broken, or pushed back pins or sockts, corosion & for resistance over it's operating range.

It's reading should be smooth, with no dropouts or jumping around, just a nice smooth change in resistance over it's operating range.

Let us know what you find.

 

Well I gave up on changing the filter. I bought the little disk type tools and there isn't any room to get leverage on the filter. I'll just have the mechanic do it. I hate it when I don't have the right tool or place to work on a rig. That's the main reason I don't do much of it anymore. I have to work at the curb in front of the house.
I'll have him check the computer too. He's pretty savvy and may be able to do a good diagnosis right off the bat. The guy I use doesn't waste a lot of time getting to the problem.

 

I would like to hear what the mechanic finds.

 

Me too. I'll let you folks know.