2003 Mitsubishi Montero • 6 cylinder 4WD Automatic • 116,549 miles

I have a 2003 Mitsubishi Montero 3.8L V6. I took it in to have the valve cover gaskets replaced because they seemed to be leaking. The mechanic had it for 4 full days and said after he changed them it was idling very rough and now has a loud ticking/knocking noise as well as the check engine light is on. The vehicle did not have any issues other than the oil leaking. Never ran rough and never had a ticking/knocking from the motor. The mechanic said he didn’t know what was wrong with it. We then took the car back and drove to another mechanic who diagnosed the issue. They said we need the ignition coil and spark plugs and spark plug boots changed. Would the severe knocking and idle happen over night? I just don’t see how we go in for one thing and now have a huge issue that was never there before. Could something of went wrong during the replacement of valve cover gaskets to cause this problem?
February 19, 2011.

As far as the ignition coil and spark plugs, damage to them is probably not likely, but damaging the spark plug wire boots, (if they have never been done), is almost a given as they are hard and brittle from age. The fact that the plugs and coils need replacement are from ignition diagnostics being performed.
The first repair shop did not necessarily, I am not siding with anyone, try to do you wrong, but did what was asked of him and probably should have told you the other issues and not have delivered the vehicle without explaining what was going on.
This did not all happen over night, but the repair of the valve cover gasket probably caused the plug wires to essentially, "Not Connect" or transfer enough voltage to the spark plugs, which certainly need replacing if they never have, and with low voltage from a weak coil, can add up to the problems you are experiencing.
It sounds like the ignition system will be straightened out and you might ask about the condition of the fuel system and fuel management system.

The intake and throttle body could be dirty, as well as the O2 Sensor, Idle Air Control Valve, (IACV), and the Fast Idle Thermo, (FIT). If the Intake tract and throttle body are dirty, that can affect performance.
I hope this helps. We are always here if you have any other questions.

The secound shop is charging me for spark plug wire set, spark plugs, spark plug R&R (not sure what that means), Manifold set, spark plug boot (coil to plug), and ignition coil. My problem is there was nothing at all wrong with my car at all except someone said we might have a oil leak somewhere. Thats when we took it in and the fist mechanic said it was the valve cover gaskets. So we said we would like to have them replaced. Thats when all the other issues came into play. After he replaced the covers the car would not stay started at all. He had it for four days trying to figure out why he couldnt get it to stay running any why there was this horrible tick all of a sudden. He was having such a hard time trying to figure out what the problem is that we started to offer some ideas. Such as not connecting the wires right. He said he switched the coils and that it was finally running better but once we got there to pick it up it was not any better. The lights on the dash are on and the ticking is VERY loud as well as a rough idle.
So really to us it feels like over night. We took it in to fix the oil leak issue so it would not cause other damage but once they get changed is when there is 900 dollars worth of damage to be repaired. Does this seem right? My thoughts were while trying to get it running with a steady idle he was driving it around the block and such. Is it possible he didnt have the valve covers right and was test driving it and caused the other issues?

Feb 19, 2011.
My first instinct is that the first shop was not very professional. When a vehicle is delivered to a customer, it should be test driven and any issues brought to attention before it is picked up. Before that happens, the car should be looked at and the service tech should take into consideration the mileage, last service done and the condition of anything he will be working around and the overall condition the car is in. A lot of people don't like it when a service tech suggests more repairs. It is selling more for the shop, but a dependable repair shop will suggest items that need to be serviced. If he had just asked when the last time the spark plug wires were replaced, a lot of this could have been avoided or you would have at least felt like you were not being blind sided like you do now. If the plug wires have never been replaced, that is a no-brainer. If they are going to get pulled, they are going to probably fail and while the plug wires are off anyway, it would only cost for the parts as this is, "Overlap Labor". Meaning that the plug wires had to be, "Removed and Replaced", (R&R), so there is no extra labor charged since they are going to be R&R'ed anyway.
So, I do agree that the first repair shop is somewhat un-professional and should have done things differently. It should not cause Check Engine Lights to come on. Switching coils should not do that and I am not sure why he did not suggest the service that you are getting done now. All I can figure is that he did not want to look bad for not telling you how much the vehicle really needed.
The $900.00 is not an unreasonable estimate considering the diagnostics the repair shop had to do. In fact it is about right for the services stated and the vehicle certainly needs them and you will be amazed at what replacing said items will do for the trucks performance. You will get better gas mileage as well. So, don't take it all as bad. The services needed to be done, you just went to a repair shop that did not tell you everything it really needed and at least tell you that things like the plug wires may get damaged. Other than the plug wires though, I have to take your side as saying something like, "maybe I wired it wrong. Or, I tried switching coils", does not sit well with me either. There is not anything I can think of that could get wired wrong just from doing valve covers. If there is, a good tech would certainly keep up with it.
So, I am sorry you are in this position and I hope that you can sort of see the good side of the situation you are in.
In the future, when picking a repair shop, although if things go well with this one, (keep using them as loyalty to any merchant is a give and take and is good for all), there are links on this site to help you find a reputable repair shop near you. Look at the condition of the shop, is it clean and reasonably tidy? Does the equipment look outdated and worn? Does the staff carry a professional attitude?
These are a few things to look for in a good repair facility, not a guarantee though.
Let me know how it turns out.

Thanks so much for your reply! The information you have given me has been very useful. Just when I thought this issue was going to be fixed and my car back to normal there is yet another problem. It seems there is a burnt valve now. After all the work and all the money I have been paying out my car is still not working. Do you think this relates to the issues I listed before? I am totally shocked and dumb founded at what s going on with my car. I literally took it in running perfect no problems (other than wanting to find the oil leak)- Compared to now being in the shop for two weeks and won t run at all. I m starting to really worry that the first shop I took it to did something very wrong.

Feb 24, 2011.
I am glad to hear the information helped but I am so sorry for your situation. Vehicles are a pain in the ***.
I do agree that the first mechanic as you described the situation. Seemed shady.

A burnt valve comes from a lean air fuel ratio condition in the cylinder. Either a injector failed on that cylinder or you had a intake manifold leak right next to the ort or an exhaust leak right nest to the port for that cylinder.

So, now am I to understand that all the aforementioned repairs are complete and the burnt valve is making the truck still perform badly or just as bad as when you brought it to the second repair facility?

A this pint I would recommend trying an On Board Diagnostic scan. If you have the repair shop that you are at now do it, it is simply hooking up a plug and reading failure codes stored in the trucks' computer. Ask to watch. I think I mentioned this to you before. I am so confused with 2 other customers, one of them has a Montero. Believe it or not, that I am loosing track sometimes.
The code reader will say right out if there is an issue. The display screen will say if there is something wrong. It still might not pick up the issue. So, ask which cylinder it is and if it has low compression form the burnt valve or how it is affecting the performance. Ask if he has an infrared thermometer and ask if he will point it at the exhaust manifold for the bad cylinder. It should be considerably cooler than the other cylinders as it is not firing. If that does not work, drop a few drops of water on a good cylinder and then the one in question as the good one should boil off the water more quickly that the failed one.

I will be unable to check post via computer for a bit. So if you can e mail me your response, I can replay to you more quickly using me cell phone.
My e mail is beck. Bradley333@hotmail. Com.
Let me now how things go and I will reply ASAP.