Codes P0305 and P0171

[FordsRule01]

Hello All. This is my first post and have a question as it is driving me bonkers. Start from the beginning. I have a '98 explorer xl 4.0L OHV 1118,*** miles with a 55rfe I bought in June of last year. I really do like the vehicle but it has given me some problems. Bought with a 30day/1000 mile warranty for the dealer and 6 weeks in the tranny took a s$%^!!! So, took it to the local shop and had it rebuilt, no problems now. Lately thought, I've been getting code P0305. I've replaced the plugs and wires and a new coil. I thought I had the problem solved, but last night it through the same code again and also the code P0171. I can replace parts (bought my extent of being a mechanic) but troubleshooting is "all greek" to me. I also have a "stumble?" about 1200-1800 RPM and it will run rough with the CEL on. However, when I reset the CEL, the roughness seems to dissipate, but the stumble remains. I have been reading the forums here for a possible answer, and I have TPS ready to put on tonight. Also, I have cleaned the MAF with MAF spray and the throttle body with cleaner. I am at a loss as to what is going on with this D*$# thing! I'm getting really frustrated with it. I need to get it fixed and it to be reliable transportation. Sorry for the long post, but I wanted to give you all as much info as possible. Thanx for all the help in advance.

 

[Mike65]

FordsRule01, welcome to EF. The codes you are getting are PO305, cylinder #-5 misfire detected, http://www.obd-codes.com/p0305 & PO171, bank #-1 system to lean. Check this link with info on what to check for; http://www.obd-codes.com/p0171. What I do when I have a CEL once I pull the code, I will do a google search. You will find helpful info, or you can do a search here.