Hi, I'm new here but I have read several posts and have not seen one that addresses my particular problem. I have an 04 impala 3.4 w/108,000 miles. Every 2 or 3 weeks for the past 3 or 4 months I go to start the car and it cranks just fine but won't start. I've learned that I can spray some starting fluid in it and it will start fine and run for a couple weeks. Just this morning, the car started fine but was running rough all the way to work. That was the first time we've had problems with it running rough. At 80,000 miles I replaced the fuel pump. I replaced the plugs and wires about 8,000 miles ago. I have checked the fuel filter and it is clean and so is the air filter. About a month ago, I ran the 3 step Berryman fuel injector cleaning system on it. I'm hoping someone has had this problem and can help me. I appreciate any help I can get. Thanks

 

Chack for loose spark plug wires, possibly broken boots. Spray some water on the wires and watch for arcing. Check to se if spark is even present at the spark plugs. Check to see if all the injectors firing.
Also, check engine light on? if so, what codes are set?