QuestionDennis,
First off I'd like to say thanks for volunteering your knowledge. I have a '97 4x4 F150 4.6L. My problem is two-fold.
1. After starting and at idle, the engine just barley runs. It shakes almost like it's missing but isn't. If I rev it up above idle it would hesitate but then rev up in response to throttle up. However, when I put it in gear there's no power at all. DTC(s) retrieved were P0171, P0174, and P0401. CEL is on. I replaced the following: DPFE, MAF, EGR valve, all with no help. I also sprayed the intake manifold with starter fluid to find a possible air leak.
2. After having done the previous I gave up and decided to drive the 40 miles to the dealer. After driving 30 miles at speeds up to 60 mph the engine quit. BTW, during the 30 mile drive I had to keep the pedal to the floor and constantly downshift with o/d off. The engine was also knocking slightly all the while. Water temp and oil pressure were normal. When I tried to start it I just hear what I think is just the starter spinning (high pitch whine), engine doesn't sound like it's turning over. I checked the codes again (I erased the originals in the process of Step 1), I just have the lean codes again P0171/0174.
Any info you can share would be greatly appreciated.
Thanks, George
AnswerSprayed the intake with starter fluid? Lucky you didn't blow something up!
Lean codes can be caused by many things. Vacuum or air leaks, especially in the PCV line or the air intake ducting. Low fuel pressure; a misfire; among others. If this is now at the dealer, why not let them check it out and see what they say? You are more than welcome to return and ask me about their diagnosis if you like. I returned to full time work today so my response times will not be as good, but I try to answer everyone the same day when possible.
I have not replaced EGR valves on Ford products since around 1990, they just don't have the problems as in the past. Most times nowadays it is the sensor that fails.
