new S10 with 4.3, engine shakes on idle, @5-600RPM. Been back to the dealer twice with no joy. They've cleaned the injectors, said it was probably bad gas, but the problem continues. Has been that way since new. Any similar experience or ideas?

try changing the plugs

how violant is it? if its pretty rouch then there might be a vaccum leak somewhere. or the distributor cap and rotor. one of them should be the problem.

the s10 4.3 is not a balanced engine when you really get on the motor it shakes hnce the nick name of the 4.3 motor the "shaker" there is nothing wrong with the motor. the mechanics you went to were stupid

hope that helps you out

The 4.3 had a bad habit of shaking. In fact, 4.3's that were on late eighties Monte-Carlos would stress or break the stamped steel motor mounts. There are now aftermarket motor mounts that were redesigned and made with stronger guage steel for them.

There is one engine worse than the 4.3 Chevy, the Dodge 3.9 V6 that went into many a Dakota. Those engines shook worse than any Chevrolet.

the s10 4.3 is not a balanced engine when you really get on the motor it shakes hnce the nick name of the 4.3 motor the "shaker" there is nothing wrong with the motor. the mechanics you went to were stupid

hope that helps you out
Easy big guy...don't go calling people stupid unless you got your facts straight..
The 4.3 in the 03 S trucks have a counter balance shaft to smooth out the vibrations caused by the engine design.

Don't spend a dime on your truck if it is still under warranty...take it to another GM dealer and have them take a look. Take copies off your previous visits to the other dealer and ask to talk to the service manager...he may be able to help you.