Running rough now

STEVE1990

MEMBER
2000 FORD RANGER
3.0L
6 CYL
2WD
AUTOMATIC
17,500 MILES

Hi, I was driving to the store last week and I smelled gas. I went home, opened the hood and was checking by the injector and saw a pinhole leak coming out of number one injector. So I went and got a new injector for my truck. (By the way the truck had no issues prior to the replacement of the injector). I replaced the injector and replaced everything the way it came off, started the truck back up and no leaking was seen so I started to go around the block and now it feels like a misfire/bogging out? I was going to replace the plugs and wires anyway so I did. No change. I went through everything I touch or moved while I was replacing the injector and cannot see anything wrong. Granted I am no mechanic but I cannot figure it out. So I did all the internet stuff I could without throwing parts at it. Checked out the MAF and cleaned the EGR (little carbon build up but better than the videos I have seen). I cannot afford a mechanic right now and need the truck for work. Any and all ideas, suggestions, and tests I can do would be greatly appreciated. Thanks in advance. Steve

1 Reply

CARADIODOC

MECHANIC
33,763 POSTS

Your truck is new enough that the Engine Computer is supposed to detect misfires and set a diagnostic fault code telling you which cylinder is responsible. Since a misfire can increase emissions, that fault code is required to turn on the Check Engine light. If that light is not on yet, there is likely no fault code set yet. The goal is to get a fault code, then, once you know which cylinder is at fault, (hopefully the one you put the new injector in), you can switch that injector with one from a different cylinder, erase the fault code, then see if a code sets again for the cylinder you moved the suspect injector to. You can do the same thing when you have individual coil-on-plug ignition coils.

The reason I suspect your new injector is they are supposed to be replaced in matched sets. Chrysler buys their injectors from Bosch in flow-matched sets, and it is extremely rare to hear of any injector problem. GM has a really big problem because they just grab a handful of injectors out of a huge bin as the engines come down the assembly line, and they toss them in with no regard to flow-matching. At first they do not cause enough of a problem to be noticed, but by around 100,000 miles, one or two will flow less than the others, then you will get a lean misfire that you cannot feel, but the Engine Computer can detect. Many GM do-it-yourselfers have pulled their hair out trying to find the cause of these repetitive misfire codes when the engines seem to run okay.

I do not know the history Ford has had with their injectors as far as flow-matching. I really have not heard of this being a problem, but to avoid that, is why they need to replaced as a matched set. I would suggest reinstalling the old, leaking injector to see if the misfire clears up. If it does, consider finding a set of injectors at a salvage yard, all from the same engine.