Code P0430

[pesky1]

I went to Autozone because my CEl came on and I got code P0430 this is a bad O2 or CAT CAUSED by misfire or vacuum leak or exhaust leak. I have pretty much ruled out Vacuum and exhaust leak which leaves me with the misfire I have been having.Can anyone tell me how to determine which cylinder is misfiring??? I have pulled every single one of the boots to do a visual inspection looking for water or oil in the well but they were all clean and dry. I am only getting the misfire at about 2000 RPM's when I accelerate and sometimes on the highway at around 72 MPH consistantly. I replaced the TPS about a month ago because the truck was losing power and bogging down when I stepped on the gas this fixed that problem but now I have this problem.
I don't want to chase my tail on this and was wondering if anyone can give me some advice
This is'nt a bad misfire yet it is just a slight bucking when I accelerate but I am worried it will get worse.
I am moving next month and need to fix this before I have to drive 4000 miles across country.
thanks in advance for any help.


2003 Expedition 4.6L XLT
71,000 miles

[TBIRD430]

Have u changed the fuel filter in the last 12-15k? Are the plugs and plugwires OE originals?

[Reginald]

The DTC code reader will tell you what cylinder is backfiring. Go to AutoZone or AdvanceAutoParts and they will read your codes free.
Reggie

Originally Posted by pesky1

I went to Autozone because my CEl came on and I got code P0430 this is a bad O2 or CAT CAUSED by misfire or vacuum leak or exhaust leak. I have pretty much ruled out Vacuum and exhaust leak which leaves me with the misfire I have been having.Can anyone tell me how to determine which cylinder is misfiring??? I have pulled every single one of the boots to do a visual inspection looking for water or oil in the well but they were all clean and dry. I am only getting the misfire at about 2000 RPM's when I accelerate and sometimes on the highway at around 72 MPH consistantly. I replaced the TPS about a month ago because the truck was losing power and bogging down when I stepped on the gas this fixed that problem but now I have this problem.
I don't want to chase my tail on this and was wondering if anyone can give me some advice
This is'nt a bad misfire yet it is just a slight bucking when I accelerate but I am worried it will get worse.
I am moving next month and need to fix this before I have to drive 4000 miles across country.
thanks in advance for any help.


2003 Expedition 4.6L XLT
71,000 miles