It is 15 psi instead of the normal 20 psi. Car also backfires through the carb and exhaust. It is a 71 Chevelle with HEI ignition.
2007-11-07 14:16:25 · 2 answers · asked by ballistikball 1 in Cars & Transportation ➔ Other - Cars & Transportation
Besides a bad vacuum hose as Tom mentioned (which would produce a higher than normal idle speed) the distributor could be installed incorrectly or the timing chain may have slipped a tooth or two. A "large" camshaft would also produce lower vacuum but would not cause backfiring as you described. If the problem began all at once when you started the car then the timing chain slipped, unless it happened right after the distributor was removed and replaced. An incorrectly installed distributor or slipped timing chain will also produce a noticeable decrease in power and gas mileage.
2007-11-07 15:50:59 · answer #1 · answered by flick12003 3 · 0⤊ 0⤋
hole or crack in the rubber vacuum line
2007-11-07 14:23:45 · answer #2 · answered by tom4bucs 7 · 0⤊ 0⤋