[quote:de4f922fea="rasmataz"][quote:de4f922fea="doogey"]I have 2001 f150 with a 5.4 engine 115,000 miles. recently it started having a rough idle during morning starts and after driving a few minutes it would clear up. Recently moved from Atlanta to Vegas. Heat in las vegas 108-115 very dry, Georgia 90-95 very humid. I had the plugs changed at 110000 and it ran good until recently. It does this all the time now. Previously I had experienced the same problem only once after it had set for a couple of months (colder months). Ford Dealer recommended 3 plugs and 3 plug wires. I think the 3 plug wire may be bad. However why would the enginer run smoothly after a few minutes?[/quote:de4f922fea]
Have you bench test the coolant temperature sensor-could also be the idle control speed device and coked up throttle body that needs cleaning.[/quote:de4f922fea]
The rough idle starts reminded me of a engine that had just had a timing belt changed before the timing had been adjusted. The dealer had also mentioned an EGR valve had intermitent problems according to their diagnostic machine. I was reading a Chilton's manual and saw that a throttle position sensor could affect timing. I replaced this sensor and cleaned the mass air flow sensor along with a similar air sensor mounted next to it and that solved the problem. Since I did these three things at one time, I am not sure what solved the problem.
The dealer wanted to charge me over $1,900.00. The plug wires they wanted to replace where actually the individual coils found on the 5.4. Its hard to believe that dealer's mechanics rely so heavily on the computer diagnostic equipment even though the diagnosis does not make sense with regard to the symptoms I described. The dealer was going to change the EGR, starter, 3 coils, 3 plugs and do a radiator flush. They told me the starter was bad because I had mentioned that at one time, the rough start sounded like a starter that was not engaging the flywheel or a starter turning an engine over with no compression.
"could also be the idle control speed device and coked up throttle body that needs cleaning." Your answer was right on point. Thanks
Aug 4, 2007 at 9:30 AM
