Hi All - 99 XLT 4x4 3.0 FlexFuel Auto

I had a bad injector about a year/15000 miles ago. It was showing all the symptoms - rough idle, hesitation at all speeds, etc. I had changed the fuel filter, tested the pressure, so on. Took it in to a local shop, and the number 4 injector was bad. They replaced them all. Ran fine up until about 3 months ago. It was doing the same things. Took it back in, and they replaced all the injectors again, under warranty. Ran fine again, up until yesterday. All the same symptoms. I went ahead and cleaned the MAF and TB just to rule them out, but it is still doing the same thing. I really think it is an injector again. I want to try some "home remedies" before I take it back in again, but looking for some input.
I had heard about adding a quart of tranny fliud to the gas, does this work for cleaning?? I have also thought about adding something else like Seafoam, or Marvel Mystery Oil, or Redline SI-1.
I know that if it is an injector again, and if I add something to the tank, I possibly will not get it cleaned/fixed. But again, I want to try something myself before taking it back in.
And I would just go back to the shop and complain, but I did go off-roading about a month ago, and went through a "puddle" that I shouldn't have. So I think that may have something to do with it...but again that was a month ago, and this has just started again yesterday. Any thoughts on adding the above mentioned to the gas??

 

Did you do any off roading before the other times you had a problem? At first I was thinking bad gas. Now I am thinking a bad seal in the fuel system that allows water/dirt to get in. I would take my gas filter off and cut it open to see if anything is in there. This could narrow your search.
Do you buy gas from the same station? My bud used to deliver gas to stations and if a small seller wanted to make a couple of pennies he would not get the additives. The additives are added when they fill the tanker truck so unlike the ads you see not all gas under a brand name has the additives. Have you filled up just after or during the tanker dumped? This raises sediment from the bottom of the tank. Yes, they tell me there are filters on the pumps but when do they replace those? No one has given me an answer on that yet.
When they replaced your injectors, what did they look like? Dirty from bad gas or something else, not getting a proper signal from the computer, nozzle damaged? Some shops have injector testers and that might help figure out what is causing the failure.

 

How was the #4 injector identified as the cause of the original problem? Was it a cylinder #4 misfire? Was a compression test done?

 

Redline SI-1 is the real deal!

 

Go ahead and do the above suggestions to get the injectors back up to snuff, but dealing with the injectors that much is definitely not right. There's other issues there as Victory indicated such as fuel problems. Can't imagine anything passing the filter that could cause it, so it must be fuel related unless the new injectors are bad.

I would try to get the injectors that are in there now cleaned and working right instead of just changing them out. If you can get them working right, it'd be a pretty good indication that it's a fuel problem rather than defective injectors

Fred

 

I find that a little acetone in the gas does wonders to clean up the fuel system and remove any carbon from the combustion chambers. I put in 5-6 oz per tank for 3 tanks in a row about every 50k miles, and after that it runs like new again. You just have to be careful with the acetone, because its a good paint remover...

I also think you have a fuel problem - do you buy gas at the same station regularly? If so, I'd go to a different station. All gasoline is supposed to have injector cleaner in it now, but my experience is that the 'name brand' gas has better stuff and keeps things cleaner.

Have you been running E85? That should help clean up the injectors too, if you have access to it where you are, since the alcohol is a better solvent than regular gas.