Hey Scooby , I had my Valk running like a top and all of a sudden on the Interstate , it started to miss out real bad and the damn popping coming out of the exhaust pipes sound just like popcorn on the freeway ... I could of sworn it was the vacum hoses because of the popping even tho I had already changed out ALL my vacume hoses ..... but guess what , I called my mechanic friend and told him the story and HE said , what heat range are you running and I said what the book calls for a 9 plug ...... he said wrong, because here in the San Antonio area where we have alot of humidity I need to run alittle hotter plug and go use the 7 plug instead of the 9 .... low and behold I put some 7 plugs and the Old Fat Lady she is running better than ever before .... He said that plugs will foul out when you least expect it and when they do go foul all the cleaning and regapping won't help ya ..... so thats my story Scoobydo and my Valk is still running " Bitchin good " so maybe check your plugs and smell them and see if you can smell gas on them , it worked for me ....

Thanks Old Geezer Richard