2007 hemi pick up. I keep having a back fire. One tech said it's a miss fire on cylinder 6&7. I changed all 16 plugs. Still problem. Changed coils on 6, 7&8. Changed the cam or crank sensor (the one right below the alternator). Still having problems. No codes are being thrown on the computer. Help please
Backfire thru exhaust confirms misfire. So how did old plugs look? Especially 6-7. And does your motor have MDS?
December, 31, 2011 AT 7:17 AM
You could try switching injectors on 6-7 with nextdoor cylinders and see if problem moves with them?
December, 31, 2011 AT 2:56 PM
The old plugs looked good. Don't know what MDS means. Do injectors get bad or do the clog up.
January, 1, 2012 AT 5:59 AM
MDS is gas saving 4cyl operation when cruisin. Injectors do both.
January, 1, 2012 AT 11:04 PM
Yes. And I notice the backfire when I let off the gas pedal
January, 2, 2012 AT 4:39 AM
I would say MDS takes this diagnosis beyond do it yourself. VVT adds extra complications to any attemp to guess at fix. You will have to take it in to get diagnosed with the right equipment and procedures.