VW Jetta Starting Issue

I have a 2009 VW Jetta SE 2.5L. It has been having intermittent issues with starting for about a year now. I have replaced the spark plugs, ignition coils, camshaft position sensor and crankshaft sensor. Sometimes the car starts fine and other times it does not. When there is difficulty starting the car, the engine light may or may not come on. Sometimes after it cranks and eventually starts it makes a noise at the end like I've overturned it. Similar to what you would hear when you try starting a car that is already running, a grinding noise of sorts. It doesn't always do that though. Other times when it's difficult to start, it effects the acceleration. I can get up to speed slowly but if the RPMs get close to 30 the car jerks and I have to let off the gas. I don't know if there is more than one part bad/going bad but it all stems from starting. Any help would be appreciated. The car has just over 100,000 miles. Thank you.