Blazer surging on 1994 Chevrolet S10 Blazer

Recently fixed a water leak problem, changed intake gasket,spark plugs,distributer cap, rotor button,plug wires and plenum gasket. Question is why is the truck surging now? It seems to want to take off on its own at times. And RPM meter is jumping just a tad. It didnt do this before what could it be?

by in Palmyra, TN on November 17, 2009
1 answer
ANSWER by on November 17, 2009
I suspect there is a vacuum leak somewhere or the throttle cable is mis adjusted and the computer is then trying to fight a high idle. Automotive repair shops have a machine that generates an inert non flammable low pressure smoke that looks similar to cigar smoke. The intake manifold is sealed off, and smoke is put into the engines intake manifold. The smoke then fills the engines crankcase and if there are any vacuum leaks from gaskets, hoses, or housing smoke emits from the source of the leak. Some mechanics will use propane or aerosol carburetor cleaner, with the engine running they will spray the cleaner or propane around the intake manifold and vacuum hoses. A leak will cause a "lean mixture" condition, when the flammable fuel (carburetor cleaner or propane) comes in contact with the source of the vacuum leak the engine idle speed will raise as the engine has received "fuel". this method of finding a vacuum leak works but is not recommended as it can easily cause a fire.
2 people like thisFlag inappropiateReply
Related Items:
While holding a steady 65-70+ mph going up steep hills (North Carolina)engine will surge or miss under load (can't tell which). Within last year replaced plugs, wires, ign cap and rotor. Within la...
My blazer runs good for a bit but then its like the engine revs up and down slightly and seems like its going to cut off and it does some time. I checked the codes and it says egr and o2 is rich. I...
when I start engine it surges bad. when I accelerate up to half throttle its okay, but more than that,it falls flat on its face and misses and backfires through the exhaust like its real lean.i unh...