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Have 2001 Exp (5.4L) with 165K. Have following symptoms:
1. Hard starts (cranks several times) - but always DOES start.
2. Idles fast (in park) with engine cold or warmed up - 1000+ RPM's.
3. Will not shift out of 2nd gear.
4. Slight rough idle (in drive) at a stop.
5. Despite symptoms above, truck runs OK (not obvious misfire, loss of power, etc.).
Have had these symptoms in the past. In most cases, symptoms have occurred after snow fall followed by bitter cold (live in MN) which is the case now. Sometimes, symptoms occur only with bitter cold. In either case, symptoms seem to go away after temps warm back up around freezing. Currently trying to warm vehicle back up in my heated garage. Symptoms do not seem to point to bad COP as I have had several fail both on this vehicle and my PU truck with same motor. Have not opportunity to pull codes at this time. Thinking it might be TPS, MAF, or EGR.
Thanks for response Alloro - just getting back to trying to solve this problem now (past xmas rat race and on vacation form work...). I did check for vac leak and found none.
A revision to my original post of symptoms below:
1. Hard starts only when engine cold - starts OK when engine warm. 2. Idles at normal RPM in park (700-800 RPM) but idles rough.
3. Seems to shift OK up to O/D.
4. Rough idle (in drive) at a stop.
5. Lack of power - acceleration not smooth
Symptoms do in fact seem indicative of bad COP. Had steady check engine lite which would intermittently blink when accelerating. As of today, have not been able to pull codes as they were cleared due to dead battery and havent been able to get OBD to re-establish fault codes.
One other symptom - with engine idling, there is a loud "buzzing" noise which seems to be coming from either cylinder 1 or 2 (passenger side counting back from front of engine). Never known failed or failing coils to buzz - could it be injector going bad?
Going to drive vehicle some more to try to get CEL to come back on and hopefully retrieve fault codes.
One other symptom - with engine idling, there is a loud "buzzing" noise which seems to be coming from either cylinder 1 or 2 (passenger side counting back from front of engine). Never known failed or failing coils to buzz - could it be injector going bad?
Going to drive vehicle some more to try to get CEL to come back on and hopefully retrieve fault codes.
Thanks in advance for any thoughts/advice!!
The buzzing could be an injector as that is a electro-mechanical device. Pick up a mechanic's stethescope,available at most parts stores, and listen to it as well as anything else that is in the area. you will find the buzzing that way for sure. A bad injector will cause a loss of power and a rough idle.
Not sure if the code is the same, but what causes a cylinder to misfire? Basically, it's one of three things: loss of spark; the air/fuel mixture is too far out of balance to ignite; or loss of compression.
Do you have a check engine light (CEL) or a code that has been pulled?
I have gone months with a slight misfire until a CEL showed up. It just depends on the severity of the problem and how well you notice your vehicle acting.
Had a steady check engine light. In addition, it would flash while accelerating. Vehical sat a couple of weeks before I had chance to get my borrowed out scanner back at which point discovered battery was dead (codes were likely cleared since CEL was no longer on and as I wasnt retrieving any with my scanner). Been driving vehical around neighborhood here trying to get OBD to re-establish fault codes but it has not yet. Not sure how much driving or how long OBD needs to determine problem?
Vehical defintely not running right. As mentioned, rough idle, lack of power, acceleration not smooth, etc. Very similar to bad coil as I have had this happen on my 97 F150 with same engine (5.4 liter). Plugs were replaced on this vehical at approx. 120K. New coils on cylinder #3 and #6 after plugs were blown out (learned the hard way twice what happens when they are not torqued down properly!!).
Determined the cause of the buzzing noise - it was PVC. Replaced with new one.
As far as rough idle, etc., bought a new COP and cycled thru all cylinders. Also checked spark plugs. All plugs OK and none of the COP's were bad. All connections and wiring looks OK as well
Truck still running bad - been driving around trying to get CEL to come back on but no luck (go figure). Just to confirm - tried to pull codes again with my scanner but none there.
Thinking about checking each injector one at a time with good one...