I have a 2002 Hyundai accent 1.5L SOHC Manual transmission
About a year ago my "check engine light" began flashing randomly...mainly when i was stopped at lights. It would always go off for a few days until one day it just stayed on. In addition to this, it was making a ticking noise and sputtering (almost like i was going to stall?) when stopped. The idle in neutral was about 1300-1400 RPMs.
At this point i took it to a shop and had about every test done on it (the codes at the time were for cylinders 1&4 misfiring). They went through every diagnostic test (replaced spark plugs/hoses etc) and still came up with the code for cylinder 4 misfiring.
Spark tests were normal, and all injectors were firing normally. The compression test showed that a valve may not be closing completely in the 4th cylinder?
They finally put a camera in and said there was a huge amount of carbon build-up and my only option was to either replace the whole engine as my car was basically running on 3-cylinders, or put carbon-out products in my engine/gas tank and hopefully clean it out, or drive it until it dies.
My car has 125,000 km on it and has been in a few accidents and in my opinion is not worth putting a whole new engine in that they told me was going to cost more than the value of my car, so i have been driving it since then (almost a year).
My timing belt/water pump were replaced last week and the shop (a different one) told me that the engine was running fine and there were no problems with it. The engine light is still on and they gave me the codes 1505IAC-opening coil circuit, and P0340-cam-shaft position sensor saying that it was just a sensor and not to worry as the engine was ok. The car is also still idling at around 1400 in neutral and sputtering while idling.
I would just like to know why the codes are now different and is it a sensor, is it the cylinder and is my car going to randomly die on the side of the road one day???
THANKS SO MUCH IF YOU CAN HELP!!!