I've got a 250 straight 6 in my mav. It runs pretty great until I hit about 60mph. After that it spits and pops and sputters and sounds like it's about to die or blow and won't go any faster. When I let off it goes back to normal. I've tuned up the engine as far as air intake, carb is clean, new spark plugs, all the basic stuff like that. Anyone know what this could be due to?? Thanks!!
a restriction in the fuel lines can cause this. the possibilities are a clogged filter sock in the tank, bad rubber hose that is swollen or has a flap restricting flow, a crushed or bent fuel line, a plugged up fuel filter, or a weak fuel pump.
sitting in park-E-brake on...how does it do when you rev. the engine up pretty high and hold it for a second or two?
Vacuum leak. Check your hoses. If it is an auto, suck on the line to the trans. Check the carb base gasket and the PCV hose and valve. Double check your plug wires too. Are two mixed up? Micah
250 straight 6 issue My sons 71 Grabber was doing the same thing a few weeks ago, we tried everything, tune up, timing, vacuum lines,adjusted carb, checked fuel pressure,compression test, even had a NOS carb we put on. . . . .nothing. then I noticed that his fuel line had gotten pushed really close to the heater core hose at the front of valve cover/ water pump . . . . .vapor lock. I simply "tweaked" the fuel line to get a little room between the two. Problem solved. It runs great now, Worth a peak. And alot cheaper than all the parts we bought!
