Question about 2004 Ford F150
My engine started to rough idle about 2 weeks ago. I know I need to replace plugs but was waiting for warmer weather. Last week the engine died at a stop light but started right back up with no further problems. The next day I got gas in the morning and didn't drive again until the afternoon. Thats when the engine started misfiring badly at idle and on the road. I threw three codes, P0301, P0316 and P0171. I changed the #1 plug just for grins with no result. I added SeaFoam in case a fuel injector was clogged. No result. Interestingly, the car seems to idle fine when cold, and gets worse as it warms up. I first thought maybe a bad coil pack, but now am wondering if I have a vacum leak thats related to a warm engine, ie, intake plenum. Any thoughts?
Same issues. changed all the spark plugs, coil packs, throttle sensor, maf sensor and injector on affected cylinder with no result. people say cam phaser however that is so unliikely as to be ridiculous, since the engine does not knock like a cam phaser. burnt valve seems more likely now. replace the head. ford is total garbage. nice truck if it works, but they always always have issues.
Posted on Oct 14, 2013
The concern is likely caused by the coil which sits on top of the spark plug. Your P0301 indicated misfire on cylinder 1. Your P0316 indicated it occurs on the first 1000 revolutions. Your P0171 indicated lean on bank one. Bank one includes cylinders 1,2,3 and 4. Your lean code is strange but could be related to misfire. I would recommend swap the coil on number one with number two. Clear the code and drive it. I would expect to see a P0302 which indicates the misfire traveled with bad coil. good luck.
Posted on Mar 03, 2009
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