Hello everyone I currently have a white 2001 Hyundai Elantra, and have had nellybell for 3 years now and she has been flawless up until now. Now I'm going to give some history here before I get down to business. About three to four months ago I was driving the car from Dallas to Austin. The car over heated when i got to waxahachie about 40 miles from home. The radiator blew and smoke went every where. I pulled the car over to the side let the car cool down and wipe up the remaining antifreeze that covered the engine. Well it took about 4 hours of going and stoping to let the car cool down enough to go a few miles at a time.
Got home parked the car and replaced the thermostat and radiator the following weekend. The car drove great and know problems. Well about 3 months before the car over heated my wife was driving the car and it went dead on her. So i brought the other car to here and fixed the Hyundai which i beleive was just neede new spark plug wires. So i bought the wires from Autozone. Well after all that about 3 weeks ago I started having this rough idle like the car did when I replaced the spark plugs the last time the car stopped on my wife. So I thought to myself well maybe I boght bad plugs so I went to the dealer and bought OEM plugs.
Well upon removing the cover that hides the spark plugs low and behold one the the plug wires had been pinched by the plastice cover. So I thought using the new plugs would sove my problems. Well for about three weeks it did but now my check engine light is on and I used a scan tool to read the code and it said P0303. I've searched on the internet as to what the code means and have come to this that I need to do a leak down test of my engine. After reading a few of the desricption on how to do a leak down test I bleive that I am redy to take on the task, but have one question about the test. How do I know when my piston is at TDC? What do i turn to advance the piston to that point. All of the posts that I read show an engine on a hoist of some sort, but my engine is in the car so how do I advance the piston?

Thanks for all your help sorry for the long post. Also feel free to email your answers to here or joseph.jackson@centexhomes.com

welcome to the forums :00000732:

PO303 is the code for number 3 cylinder miss-fire which would mean a bad plug,plug wire,coil pack,cylinder head gasket or low compression......have you got a compression tester?

please post in future in the 'elantra' forum

No I do not have on ea compression tester just yet but plan on getting one soon. I apologize for putting this thread in the wrong location.