02' F-150 Sport 2WD Triton V8 4.6L COP's. Rough Idle. In drive or park. Symptom appeared immediately. Check engine soon light came on 2 days later (not blinking). Often lose power...normal breaking into a turn, lights dim, brake power dies, steering tight. Some bucking/spitting while gradually accelerating out of turn. Increase acceleration swiftly and she smooths out and gets up a little, but still notice weakness in power. Also cruising at 55, let off gas and she'll hold rpm for 10-15 sec and then deccelerate as it should when I took foot off. Local mechanic doesn't know. Already tried Mass air flow and Idle air control sensors. Could this be vaccum leak or throttle position sensor?
Engine Idles Rough on 2002 Ford F-150
by Visitor in Carlisle, PA on October 20, 2010
2 answers 2 comments
ANSWER by ZeeTech on October 20, 2010
What codes where registered in the ECM when they scanned the system? The throttle assembly might need some cleaning. I'd also check the EGR valve, make sure it's not keep stuck in the open position. Zee
Thank you. I'll try those next. Truck has 108,000 miles. Time for indepth maintenence.
ANSWER by DaveJM on October 20, 2010
I'm thinking you could also have a fuel control or supply issue. Just a hunch until you get the codes out of the processor, as Zee said.
Thank you. The local mechanic said there were multiple codes. I should have had him write them down for me. I'll get the codes again. Maybe I'll invest in a scanner.
my truck idles rough and my heater will not blow hot , but yet the temp. is normal so it's not the thermostat,what could it be?
problem has just started. obdII memo scanner shows codes po156,po161 and po171. these are bank...
Intermittent rough idle may be caused by the EGR sensor sticking, causing the EGR valve to stay slightly open. Our technicians tell us the valve and sensor must be replaced together to correct this...