Mustang Gt 5.0 (Holley System Max and dyno tuned) runs great all winter and now that the temp is going up (90 degrees in Texas), the car is running ugly. The engine starts to shake, which in turn makes the whole car shake. this will happen even if the coolent temp is in the O or R of NORMAL. Under load, when the temp is hot, the car starts rattle and pings too. Any suggestions to fix this issue. Newbie (first forum) but 3rd 5.0 and can't figure this one :'(. Thanks.