I have a 2003 Montero Limited that runs great some times then out of the clear blue she stumbles then throughs the random misfire code. then sometimes she warms up and wont idle. then the check engine light goes out and she runs like a top again. any body know what the heck is going on? What I've done to her to date. I was getting the famous lean bank 2 error code. checked all vacuum lines, intake gaskets and o2 sensors. Finally discovered the intake that has the butterflys in it was leaking where the rod holding the butterflys comes out the front of the intake. Couldn't find a way to replace the plastic seals, had to replace hole intake manifold. fixed the problem anyway. turns out she sucked a couple butterflys into the valves and chewed them up and took them into the cylinders. [ no damage]. Changed timing belt, pullys and water pump. Replaced ignition coils and plugs [pain in the butt]. Really, have to remove the intake manifold to change plugs? And wires. Anyway, PLEASE any help would be great!!! And if anyone can please tell me what else I need to know about common problems with this rig I'd appreciate it. I do love this Monty. Thank you in advance.

 

You need to plug in a codereader capable of reading live data. It almost sounds like the misfire/misbehavior occurs when engine switches from Open Loop to Closed Loop cycle. You need to confirm that and see which parameters are out of norm when that occurs.

 

I have one but I don't know what the heck I'm looking at. I have the PAJERO manual but it seems really hit and miss with info. And I don't have a couple hundred bucks to buy a service manual. That's if I could even find one. I'd like to know how to test the crank angle and camcam shaft position sensors without just shotgunning parts.

 

You need an oscilloscope and knowing how to use it in order to test crank and cam position censors. I have not seen any other ways of doing this without a $2000 Mitsubishi MUT-II tester.

 

Yikes! I guess I should just replace the camshaft position sensor. My research tells me that will give me those exact symptoms and its cheapest. I just hate putting parts no it without being absolutely sure. Thank you very much for taking time to help me out. Do you know any of the other most common problems with this year and model? And what to check, look for and be aware of?

 

I don't know the engine on 2003 model. From what I've seen on the forum the butterfly valves is the most common issue. Don't throw parts at it. Try to see the Open Loop to Closed Loop switch over and see if you notice something with the sensors. Shotgunning parts at these vehicle is expensive and often caused problems further down the road (they have a bad reaction to aftermarket parts )

 

I,ve got the 3.8 V6 6G75

 

HunterD
I talked with you awhile back about my crankshaft position sensor. Y told me I needed a $2000 Oscope tocheck it out. Well I can't hardly afford more than I payed for the car to check 1 sensor so, I changed the sensor. Now it cranks, drains the battery and throws crankshaft sensor malfunction code. I've had the front of the engine apart 3 times checking and double checking the sensor, timing belt and sensor plate. Alls well. Today I will try to put the old sensor back in and see what gives. Do you have any usefull suggestions? Anything that doesn't require me to buy equipment that will cost me more than taking it to a dealership to have it fixed?

 

Xjfire, I never said you needed to buy a $2000 oscilloscope. I said you NEED an osciloscope in order to properly test crank position sensor. Guess what - I'd love to have one of those myself but I don't, even though I do all my work on my vehicles. Some day I hope to get one, but that day had not come yet.
What I was referring to is trying to avoid the exact situation you found yourself in now - you had new sensor installed, had the engine apart three times snd you are still in same place with the same fault as you started - the issue persists and the cause is still not diagnosed or resolved. Why? Because you did not DIAGNOSE the problem. You went on fixing a symptom based on the hunch.
I was advocating against blindly throwing parts at the engine. This approach rarely works on Montero and is a very expensive way to fix anything. If you run into a situation where you can't figure out what is going on, take it somewhere to have it properly diagnosed. You can replace a faulty part yourself, but you need to know which part needs replacing.

 

Ouch! I guess you sure told me. It's just with all the advice I see you giving on these forums I thought you might have some helpful advice on what I'm trying to do. Nothing personal but take it to the dealer isn't really the advice I was hoping for. I can't afford to take my vehicals to a dealership to have them diagnosed every time theres a problem with them. All I can do is research it as much as possible and go from there. Not trying to argue with you. I was genuinely asking for help from someone I can see clearly knows more than I do with these Mitsubishis. I thought I had the problem singled out but now I dont know what the heck is going on. I put the new sensor in and get crankshaft sensor and camshaft system circuit errors. I put the old one back in and all should be as it was, buy no. Now I get crankshaft system circuit error with it. Nothings changed except for removing the sensor, trying, unsucessfully, the new sensor then putting the old sensor back in. Your right about one thing for sure. Now I see I was wrong with my research and first diagnosis because now I see my OBDII scanner will infact tell me about the dang crankshaft sensor. And also I apologize for coming at you like that. I just came in from my Monty and I was frustrated.No excuse, I get it. I'm sorry. I'm way confused with this thing. I look at the Pajero manual I have and the manual I downloaded and they both show me how the sensor is supposed to go in yet, I just saw a posting on here from some time ago same year, make and engine as mine with a picture of the sensor mounted totally backwards from what my manuals show. It makes more sense mounted that way. So the sensor blade passes trough the sensor. I tried both new and old sensors each way. Now I'm trying to find the whole circuit to explore. I'm kinda lost at this point but I've got taking the front of that engine down to the timing belt to about 15 minutes.