Re: Misfire issue???

Posted by David Grubbs On 2014/11/29 18:23:51

That is possible, if the gasket is leaking, allowing compressed air and gas to leak from one cylinder to another. A compression test should help check that out. My 39 120 had a terrible misfire or backfire at highway speeds. the culprit, I suspect turned out to be a sticky valve(s) that were not completely closing. The sticky valves problem has been with us since the cars were new, if you read the service manuals. If you start the car, run it until it is hot before shutting it off. Plus I'm a great believer in Marvel Mystery Oil in the gas. The valve on my car stuck for several days until I took it out for a long drive and it finally cleared up.