A: Tom, I have run into similar issues in the past and found out that the culprit was either my plugs were 1 range too hot (I am currently running NGK TR5-5 but should be running TR5s and the ping factor is causing my knock sensor to cut engine power at operating temps) or the camshaft was dialled in too far advanced. Sometimes on the 4.2L, it was cam walk changing engine timing parameters while under load (cam button bolt and timing cover from a 4.0L cured that) From: Tom Jennings <tomj@xxxxxxx> Subject: [AMC-List] Duraspark distributor woes (258 six) To: AMC List <mail@xxxxxxxxxxxx> Message-ID: <Pine.LNX.4.64.0610242148210.2126@xxxxxxxxxxxx> Content-Type: TEXT/PLAIN; charset=US-ASCII For some months I've been having trouble getting the timing right on my Hornet's 258. It would either retard-backfire or ping, with little adjustment range between the two. 2.73 axle, 904 auto, weber carb. I've been running cheapsh*t gas. It's a Duraspark II (square coil, big Ford cap, etc). I'm getting 19 mpg, down from a high of 20, averaged over full tankfuls. (I've recorded every single fillup since May 2005). _________________________________________________________________ Add a Yahoo! contact to Windows Live Messenger for a chance to win a free trip! http://www.imagine-windowslive.com/minisites/yahoo/default.aspx?locale=en-us&hmtagline _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com