Just bought a 2004 Venture and was told that it needs a tune up and all. Has 100K. Starts up every time with no issues. But at idle after start up, will run rough. Start to drive, smooths right out and runs good. Come to a stop, runs rough. Also noticed the check engine light would flash periodically. I have not done anything to the vehicle yet, as I would like some input on what it most likely could be because we are on a budget. Doing some digging myself, I read that with that code, it could possible to the ignition coils, ignition module, crankshaft sensor, cam shaft sensor, spark plugs, or fuel related.

Any insight is greatly appreciated.

Thanks in advance,

JH

 

Well, the dreaded OBD II code P0300 is always trouble.

If you can get/borrow a more expensive unit, it can often nail down the exact problem, that the cheaper scan tools cannot.

 

Found and fixed the P0300 code in my situation. First checked the plugs, found 2 different brands, along with gap problems. I just bought the vehicle so who ever did the service prior didn't care. Got factory new ones and wires. Gapped and replaced. Still ran rough. Used a spark plug inline tester between the coils and wires. Found coil pack 5/2 dead. The other 2 were golden. Swapped and repeated test. Found coil pack 5/2 was alive and 4/1 coil pack was now dead. This verified the ignition module was faulty. Replaced, cleared code and boom, runs like a new car!

Hope this can help someone else down the line!

Best regards,

JH