Help, I have a 302 with 215,000 miles on the motor. About a week ago check engine light comes on. So, i took it to auto-zone. It came back with code for mass air flow sensor. I got a new one installed, Did not fix truck. My problem is it has a spark knock, Then when i pull a trailer with a load it is a terrible spark knock. I had it checked again today, They said it could be the capteur sensor under the trottle body. Again i installed a new one. This did not fix the truck. I have installed a new fuel filter, checked the Gap on the plugs, and checked for vac leaks. Please help if you know what my wonderful 5.0 problem is? I don't know about 02 sensors. Again the motor has a heavy spark knock. Thanks mstapleton