OK, 99 Ranger V6 4.0 OHV.

Having a really rough running/idling engine of late. An old buddy that I used to jest with over Ford vs. Chevy would always say, "FORD, Fix Or Repair Daily". Boy was he right. It never ends with this thing.

Anyway, I used Forscan to do a little diag. I'm still in the process but wanted to bounce some long term fuel trim data off of whoever wants to jump in. I'm going to do a 'relative compression test' when I get my new Amp reader that will mesh up with my PIco software. Anyway, Forscan told me I have misfires on Cylinder 1 and now on Cylinder 6. So started it up a little while ago to test fuel trims. Ran like crap at first. After it warmed up a while (5 min) and I snapped the throttle a few times the misfire cleared up and stopped. Actually had the misfire counter was around 4015 when it stopped counting. Anyway, when I looked at the long term fuel trim on both banks they were both around 22! Yikes. Compression tests (not with Forscan but old fasioned screw in spark plug hole type) were in OK range on bank one side. 145 on cyclinder 1, 140 on #2 and 3 cylinders. Haven't done the other side yet. So, I'm leaning toward dirty or plugged up fuel injectors. I can feel injectors 1 and 2 pulsing with my hand and Forscan does not show any failures with injectors. What would you guys guess at? The same?

Oh, put a spark tester on cylinder one plug wire and it lite up very bright. No wire or coil issue there. Also, plugs only have about 2000 miles on them.

Thanks,
Chuck

 

ck Scanner Danner YouTube

 

Are you suggesting to check out Scanner Danner? Actually, I've watched many of his videos. Also, I like PIne Hollow Auto Diagnostics. These guys and many others have really upped our collective awareness surrounding automotive diagnostics.

 

how old are the O2 sensors? and whats the mileage?

 

Not sure how old the O2 sensors are. Could be about ten years and 60 to 70 thousand. Best guess. The voltage readings with Forscan looked normal and stable. I'll get back to you with the readings.

 

you can check here but they need. to be replaced at 100k or 10yrs. they are one of the sensors that do wear out .

 

So, O2 sensors seem to respond as they should. Sorry, still don't have that data, but I'm chasing another one today. Finally got a Harbor Freight fuel pressure tester to work. Long story, so I will cut to the chase. Taped in to the Shrader valve on the fuel rail and go 60 lbs steady at idle and higher RPM's. Problem was the pressure dropped off immediately. This Ranger has a return-less system. I've got to think there is a malfunctioning check valve at the pump in the tank. This is a new pump with barely 2000 miles on it. So, just how much of a problem is it to have pressure drop? I had noticed a little bit of a longer crank to start. Now I know why. But, other than that, what other issues might this present?

I'm going to post this question in a new thread as well to see if it gets more attention. Ron D., I would appreciate your input as well.

Thanks