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Ford Explorer Community - Maintenance - Modifications - Performance Upgrades - Problem Solving - Off-Road - Street
Explorer Forum Covers the Explorer ST, Explorer Sport, Explorer Sport Trac, Lincoln Aviator, Mercury Mountaineer, Mazda Navajo, Ford Ranger, Mazda Pickups, and the Ford Aerostar
Make sure the sparkplug wires are in the correct firing order. You can find a diagram on this, I forgot what it is exaclty but I think 1,2,3,4,6,5. Yeah the 6 comes before the 5. Pull a diagram of firing order online.
Yes, anything more than 10ish either plus or minus total fuel trim can be suspect.
Positive fuel trims could be a vacuum leak, and extra fuel is added to lower emissions or make the car run. This creates a rich condition.
Neg fuel trims mean the computer subtracts fuel, sometimes in a desperate attempt because of a bad fuel injector. Lots of extra fuel could be making its way into the engine.
Extra fuel creates a campfire in the cats, and destroys them.
A new cat should never be installed for no reason. I think in California you have to certify and sign to the reason, even if you are a DIY
Unless like in my case it rusted thru- it must be properly diagnosed. Good OEM converters should last the life of the car.
if you leave your truck misfiring for too long it will destroy your cats, so if you are noticing rough idle and long term fuel trim not close to 0 time to check for vacuum leaks or replace plugs and coils. Once you have 1 coil acting up, replace the rest. if you replace the cats without fixing the misfires then the new cats will soon need replacement again.
Just picked up the Explorer today from the shop that replaced the whole catalytic assembly. Wow the difference in that engine now! It even sounds a bit more Mustang like at idle and low rumble at take off. My son loves the aggressive sound, my wife not so much. Not sure of the brand they used but the rear cat is not quite as huge as the stock one was. But it's back to running like it should. I hooked up my scan tool and all is well!
Just picked up the Explorer today from the shop that replaced the whole catalytic assembly. Wow the difference in that engine now! It even sounds a bit more Mustang like at idle and low rumble at take off. My son loves the aggressive sound, my wife not so much. But he drives the Explorer to school. Not sure of the brand they used but the rear cat is not quite as huge as the stock one was. But it's back to running like it should. I hooked up my scan tool and all is well!
