I think I am headed in the right direction but need to know possible cause of misfire.
History - 2000 taurus SEL duratec DOHC
, 189,000 miles. I used to be a service advisor for Ford dealer and have done maintenance myself in the past on this car, bought it new in 2000. Engine had rough idle when engine is cold but ran fine when engine warmed up. Had this for a couple of months but just thought it was the IAC
and would replace when I did my tune-up. On 11/30/11, CEL
came on with P0171,P0174, P0301 and also had some vacuum leaks you could hear so on with the tune-up.
Replaced plugs (motorcraft), upper intake manifold gaskets, PCV
valve (hose not cracked), replaced recirc vacuum lines from valve covers to side of air intake at the throttle body (both cracked completely disconnected).
Ran fine for a few days then CEL
back on. Codes this time, P0401, P0171, P0174, P1504. Went ahead and replaced throttle pos. sensor and IAC
but knew I was dealing with vacuum leak.
Ran good for a couple days and CEL
back on. Codes now were P0122, P1504, P0171, P0174, P0301. Did not clear codes yet, wanted to change DPFE
Went today to purchase DPFE
, not installed yet, however, went ahead and cleared all the codes today due to engine vibrating violently, and sputtering all gears and speeds. Felt like a misfire. CEL
back on in a few miles and flashing this time, checked codes and got P0401 (have the DPFE
to replace), and P0301.
I will replace the DPFE
but I have kept getting this P0301 for cylinder #1 misfire even after I changed out the plugs.
My question is, does anyone think the EGR
insufficient flow could cause one of the new plugs to foul or could the coil pack for #1 cylinder finally have gone bad and just be a coincidence? Or will this improve with changing the DPFE
? I don't want to throw a new coil pack at it if it could all just be from the DPFE
or a clogged EGR
did not looked clogged when I changed the plugs).
Sorry for the long post but wanted to give all the background info.