Cylinder 6 Misfire and then some...
 

Please help! My mechanic just called to tell me he thinks I should walk away from my 2003 Montero Limited, but I really don't want to.

2 or 3 times now my Montero has misfired in the 6 cylinder. When it happens the car shudders and if I slow down to much it starts to lose power, if I slow down enough it dies. On start up I have to give it a lot of gas to get it going and then have a rattling/tapping sound. The first time this happened mechanic pulled the plug for the 6 cylinder and the plug had literally been smashed. They weren't sure why and just replaced it. The second time this happened, on a brand new plug, they just regapped the plug. This has just happened again and my mechanic is saying that the only fix would be to remove the head and pull out whatever is in there rattling around and smashing the plug. They believe that this fix isn't worth it and I should walk away from the vehicle. The vehicle is also due to have the valve cover gaskets replaced and needs new brakes, but other then that, it had been running great. I'm looking for any thoughts on this issue. Could a piece of carbon rattling around really cause this kind of damage? Are there any other ways to burn that carbon out without removing the head? Also, why am I only hearing this noise after the misfire? I know its hard to diagnose without seeing and hearing what is going on, but I've seen a lot of great answers on this site and thought I would give it a shot.

Thanks for looking!

A good mechanic shop should have a little video camera that can be fed into the spark plug hole to examine the cylinder condition. If they don't have one, you can get one off the Harbor Freight, however I can't tell you if that will work or how good the quality is on those cameras. I'm puzzled by the "diagnosis" that something is just rattling inside the cylinder. If something is there rattling around - it is destroying your valves, cylinder walls, etc. The reason your mechanic wants you to walk away, is they know they can fix it and resell it very quickly. Have them look inside the cylinder. If this, as you say, just a piece of carbon, you can fit a vacuum to a thin plastic hose and try to pick it up from inside. By vacuuming and looking back into the cylinder several times, you should be able to clear it up. Where about are you located?

Hunter, last I spoke with the mechanic I asked them to regap the spark plug again and go into the firing chamber with a magnet to see if they pull out anything metal and then with a vacuum in case there is any carbon. I do not believe they have any kind of scope. I did talk with a Mitsubishi dealership about having them looking it over and giving me a second opinion, and they mentioned scoping it. I get wary of dealerships because I can't afford to dump thousands and thousands of dollars into the car, but felt like they might be better equipped to diagnose...we are just west of Denver in Colorado.

At the very least definitely have the dealership take a look inside the cylinder. It will give you a good idea of what you are dealing with and if there is any extra damage there already.