1997 Monte Carlo Low Throttle Miss


#1

When cruising my engine randomly has a miss. If I step on it, not necessarily full throttle but some, the engine pulls fine no miss. I don’t think it’s ignition because it doesn’t miss with increased throttle. I have looked at an analyzer and none of the sensors is showing a fault. I have put 20 tankfuls of fuel with cleaner through it after I put a new fuel pump and filter on and I only use Shell now for the last 10 fill ups. The miss is not a passive drop in rpm but more of a buck.


#2

spark plugs? fuel filter? air cleaner?

I m a fan of checking the easy cheap stuff first


#3

could the rotor arm be worn?


#4

If you think a miss is fuel, it will most likely be ignition. If you think a miss is ignition, it is most likely a fuel problem. This is an automotive corollary to Murphy’s law. This one has bitten me far more than I’d like to admit.

You’ve addressed fuel, now address ignition. This car is 17 years old, if the plug wires are original, start with them. Next change the spark plugs. Next are the ignition coils. You have 3 and any one of them could be at fault. When you change plugs, if you find one all sooty, change that coil pack. They are about $20 each.


#5

if fuel and spark is fine like the other 2 mentioned do a compression check and dont rule out a head gasket cause i believe this year falls into the notorious coolant problem recall. o and check the coolant if its orange your might need intake gaskets too


#6

When the sensors detect a light load (as opposed to accelerating) the computer will lean up the fuel mixture making it harder to ignite. This will cause a misfire if you have a weak spark. As mustangman said it could be plugs, ign. wires, or a coil pack starting to fail.