Hello all im posting this for my buddy. His 2000 ranger went on the fritz the other day. It had a really rough idle and would miss. I ran the codes and they were a p0401 and a p0305. I found that a plug wire had been burned through and was arcing. We fixed the wire and it cleared up. But when it got warm the rough idle would come back. I checked out the egr valve and it was free and not too dirty. Checked the pipe for cracks and leaks but there was none. So we replaced the egr vacuum solenoid and still rough idle when warm. Then it threw the p0340 camshaft position sensor. So we replaced that. Still runs rough. Cleared the codes and had him take it for a drive. When he came back it threw more codes p1409 Electronic Vacuum Regulator (EVR) control circuit malfunctionand p0171 System Too Lean (Bank 1). So thats why im on here now...lol! I believe it has to be egr related because it runs fine when cold but crappy when warm. Any help would be greatly appreciated. Thanks in advance!

 

How did you fix the plug wire? It should be replaced. Did you check the plug itself for damage? I would even consider checking/replacing all the plugs and wires.

The EGR problem could be contributing to the poor performance, as well. A couple of excellent articles on diagnosing Ford EGR/DPFE problems:

http://www.tomco-inc.com/Tech_Tips/ttt35.pdf

http://www.tomco-inc.com/Tech_Tips/ttt36.pdf

 

Sorry for the delay and thanks for the reply. Yes we did replace the wires. We also checked all the plugs on the drivers side of the engine and i thought they all looked a little on the lean side. Yesterday a friend of a friend works on cars for a living and he brought over his $2500 diagnostic machine and said the coolant temperature sensor was bad (we replaced it) and it has to be one of the injectors going out. So when i got off of work we took off the intake and ohmed out the injectors and all were about 14.6 ohms when the engine was cold. On the passenger side of the truck you can get to the injectors without removing the intake and they about 15.2 ohms after the truck was ran for a bit. Is it a possibility that one of the injectors is bad but doesn't fail til it gets warm (thermal issue)? Since the intake was out we blew air threw all the passages ( and all the egr vacuum passages) and sprayed them out with carb cleaner til the fluid coming out was nearly clear and reassembled and took it down the road once it got to normal operating temperature it began running rough again (but it hasn't threw a code yet). We also did a compression check on the drivers side of the engine and the readings were cyl 4 #140 cyl 5 #150, and cyl 6 #150. The only egr components we did not replace is the egr valve itself and the stepper motor piece on the intake. But we did remove them and clean them up. By the way what is the correct operation of the stepper motor piece? Is it suppose to spin or move up and down? Is there a way to check it when removed from the vehicle by applying some power? Thanks in advance!