Working on a 2008 Crown Vic police cruiser w/ a 4.6L, VIN #2FAFP71V68X127296. Has been in for runnability issues, only codes ever set were inactive (PO109/MAP or BARO pressure circuit intermittent & PO452/EVAP system pressure sensor low). Replaced fuel pump on 08/27/10, battery on 12/27/10 and fuel injector sensor on 04/08/11. The local Ford dealer had it for 3 weeks and never could get it to act up or set a code. Drove it 3 miles back from the dealer on Monda and bogged down 4 times (never shut off) and backfired once when I kept the gas pedal down. Drove it 2 miles to post office Tuesday and bogged down 3 times but hasn't happened since. Have driven it home 80 miles round-trip the past two nights and is running fine. Running out of ideas and hope you guys can help.
I had an older Chevy that I worked on that kept doing that until I replaced the fuel filter.
The backfire tells me you should check the timing and run some injector and valve cleaner. Was the backfire out the tail pipe or through the intake?
Were the inactive codes cleared? Have you checked for new codes in the past couple of days?
January, 26, 2013 AT 11:53 AM
I had this same problem with my 2008 crown vic. I had the injectors cleaned up and changed the spark plugs this solved my problem.