Engine Lopes at startup

Mu engine will occasionally lope at startup. If I look at my scanner the fuel trims will suddenly go negative up to - 20 and then the engine smooths out. It seems to happen in open loop and when in closed loop the fuel trims balance out. I changed my maf sensor, but it did nothing. I don't smell any gas, no Check engine light, any ideas?


1998 Chevy Venture LS
240,000 miles
Engine replaced at 165,000
Platinum plugs replaced at 165,000
Plug wires replaced at 190,000

check that you have good ground from your starter. and good power to your starter

check that you have good ground from your starter. and good power to your starter

I never considered the starter because the engine starts right up with out a problem. The loping occurs after it has started. Do you still think it could be the starter? Thanks

no not if it starts