Greetings. Maybe someone can help me out here. I changed the original motorcraft spark plug when my 05 ST turned 100,000 miles. Now I have put 4,000 mile on the new Autolite Double Platinum APP103 plugs. I noticed a poor gas mileage and sometimes it hesitates on acceleration. I did not notice this when I had the old plugs in them. Any advice is appreciated.
BTW, when I removed the old plugs the gaps were about .085 all around. I gapped the new plugs to .055.
Thanks
BTW, when I removed the old plugs the gaps were about .085 all around. I gapped the new plugs to .055.
Thanks