hesitates when warmed up at stop signs and signals, appears to shudder if given too much gas. recent tuneup. replaced fuel filter which was loaded with crap and some water. drives great on highway 4.3 vortec, 115000 miles

What engine?
Any check engine lights on?
How is the fuel pressure?
You might want to recheck the fuel filter.
If a lot of water still in it run some heet/alcohol type stuff in the tank.

What engine?
Any check engine lights on?
How is the fuel pressure?
You might want to recheck the fuel filter.
If a lot of water still in it run some heet/alcohol type stuff in the tank.

no lights on. haven't checked the fuel pressure, but the tank was changed before we bought it.

4.3 liter vortex, no lights, haven't checked the fuel pressure yet, but I will. could it be anything with catalitic converter or o2 senser? The gas tank was changed before I bought it

Check fuel pressure and recheck fuel filter.
Post back fuel pressure readings.
Cat/exhaust blockage can be checked with a backpressure or vacuum gauge.
MT