problem is cylinder 3 misfire. truck now runs rough at idle all injectors tested good now after i replaced the bad one in cylinder 3. just replaced sparkplugs and wires, its a electronic ignition, replaced downstream o2 sensor. battery is brand new truck has 200,000 miles on it ran fine until the other day revved it to 3500 rpms and started to run funny, but seems like not on all cylinders it is getting spark on all cylinders and tested compression it is at 175psi all cylinders. fuel filter is new. havent tested fuel pressure. just lost ne help would be awesome. had a tech scan tool on it nothing stood out besides o2 sensor and cylinder 3 misfire.

 

It's possible the new plug and/or wire for #3 is faulty. Did you keep the old plugs and wires around somewhere ? Throw 'em back in #3 and see if it helps.

 

tried it and doesnt help.this truck is getting annoying

 

I had same problem in my wifes Honda. The new plug wire went bad after 5000 miles or so. I thought the trans was going.... I would double check the gap on the plug and the wire. After that, it sounds like a computer problem.

 

Did you use the same brand plugs? I went from Autolite Platinum to double platinum, and it has a small miss at idle. i went back to the others, and it purrs like a kitten.

 

ITS NOT THE PLUGS!!!!!! thanks guys but they are ford motorcraft oem and so are the wires the gap is proper and i tested the coil today it has 13 to 15 k ohms on all matching cylinders that fire together the truck still detects a cylinder 3 misfire on the genesis scan tool. tested fuel pressure tonight it was at 55psi which is within spec. i appreciate the help guys but its not as easy as plugs and wires. connections to coil are all good no corrosion. pcv valves all function properly pulled valve cover and springs are good,which i suspected cause of the compression. im new to the site and really would appreciate any other ideas out there thanks.

 

It was just a thought!!!!!! Trying to help you out!!!!!!!!!!!

 

i kno sorry jus aggrevated jus had the trans rebuilt 1,000 miles ago and cant even drive it during the warranty. the truck is goin to the ford dealership soon. ill let them swap out parts doesnt cost me nething for them to try parts that dont work. when i bring there i will give full write up of wat they find.

 

not that simple all injectors have about 14 ohms resistance sorry there all good.

 

that is NOT really the only way to test them. i had one not check out on ohms thats why it was replaced and yes the genesis is a scan tool it did not detect the injectors. all the pulse witdhs are within spec. Its goin to ford dealer soon ill let them throw parts at it if they have to, hopefully not. as soon as its fixed i will let everyone know wat this things major malfunction is.

 

went to dealer and they said the injector i put in was bad. and the plug was fuel fouled i think the injector i had was fine and that the sparkplug WAS fuel fouled cause we didnt replace it. but to avail to the dealer it is now fixed

 

coil pack?

 

no not the coil pack it runs fine now it was a fuel fouled plug and the fuel injector

 

Hello everyone I have a 1999 ranger 3.0 flex fuel with the three catyliatice convertes. having trouble finding the front y pipe with the two cats on it. Has anyone ever eliminated those two cats and just kept the rear cat with out triggering a check engine light?