I have a 2000 f150 Ihave replaced all COPs in last year(Autozone) as well as all plugs(Motorcraft). Recently I have had 3 codes thrown for P035x 3,5,7 day 1, 4,5,8 day 2, each of the last 2 days! What could cause 3 codes one day and 3 different the next? Also truck died at idle on 2nd day but fired right backup and ran fine although a little rough. Any help would be appreciated as this has been an ongoing problem the past year, usually one P035xcode at a time about one a month,clear code and it seems to move to another cylinder! Thanks!!!!!!!!

 

Sounds like an electrical issue. Any other codes? I chased this kinda problem on a Jeep. Would throw a lean code first and eventually begin the miss fire crap. Turned out to be bad wiring behind the engine. I replaced and cleaned EVERYTHING under the hood and finally gave up and had a mechanic work on it... Took him 3 days to find it...

Good luck man!

 

Thanks for the reply! I went out this morning in the snow, and did a quick look around and saw the wire harness was against the ac accumulator which I noticed jbrew had said could cause the miss. So I zip tied it away from it. I disconnected battery to reset system to see if it helps. I had otherP030x codes which led me to replace the COPs at first, but a friend has all the Ford scanner cds on his computer no lean condition, only thing we found was the alternator reading a little low at least according to the scanner specs believe it was around 14.6? Changed fuel filter, going to inspect wire harness for rubs when I can get it to a garage. I hope its something I can find Dont want to pay dealer to fix it!

 

I had a similar problem on two of my trucks. The first time I had the problem the check engine light started coming on all the time. The engine became slugish and seemed to have no power. The engine also missed and spit out different codes at different times. The dashboard gages also started going crazy. I replaced alot of parts and spent alot of time and money to no avail. In the end the problem was corrected by replacing two grounding straps for about $12. I replaced the engine to chassy, and the engine to firewall grounding straps. I then disconnected the battery, cleared the codes and the problem went away.

Here's the cause. The engine to forewall strap from the factory swung from the back of one of the heads over the exhaust pipe and manifold area to the firewall. Over time the original copper stap becomes brittle from the heat. Then its just a matter of time before the vibration starts to crack the wires. When the stap becomes frayed and cracked it will actually not provide a consistent ground signal. This will reak havoc with your on board computer and cause all kinds of stange problems that make no sense. I would try to replace every ground strap wtih a heavier, shorter one if possible. Make sure every electrical connection is tight.

I am new to the sight, but not new to the problem. Good luck.

 

Ill check both theseground wires, Im really thinking its a wiring issue but had no idea where to start other than harness to coils. Thanks for the input! Glad to see someone was able to get it fixedthough, every time I get a scanner put on it nothing shows up on the Ford software hope its just a groun just gotta find it!