I accidentally posted this sev mins ago but most of it was deleted--so here's a 2nd try! I also apologize for asking if this has been addressed before. I'm new to the forum and I searched the topic "stalling". I found questions but I couldn't find answers that addressed some of my problems. I have been taking my 2003 Montero limited to the dealer mechanics since I purchased it new from the dealership. I have tried to take very good care of it.

Lately it seems I've had no luck with the mechanics at the dealership. I don't know if the vehicle has reached a point it can't be repaired, I question the feedback I've gotten, and (I hate to even say this) but I hope they wouldn't take advantage of the fact that I'm not super savvy when it comes to vehicle repair.

Sometimes, when I stop at a stop light, the vehicle stalls. It doesn't happen all the time. The dealer changed one oxygen sensor a year ago and replaced the throttle body 4 weeks ago. It only had a 30 day warranty for the work. Now 4 weeks later, it stalled again. Since it doesn't stall all the time, I'm not sure if the new throttle body worked at all. It seems unlikely to me that the throttle body needed to be replaced last month and now, 4 weeks later, it needs to be replaced again?? The mechanic said now the valve cover needs to be replaced and said it is leaking oil onto the spark plugs. Yet that wasn't a problem last month. I'm confused and I'd love to hear if anyone has had this experience or other suggestions. Over the past year I've taken it in several times but I'd have to look at my records to see exactly what they've done. It's been nonstop repair bills. It still looks new on the exterior and interior so I'd love to keep it going a little while longer.
I only know a little about mechanics, but I'd love to learn more!

 

Sounds like your mechanic operates on the "swap all the parts that are removable" principle. This is more common with low end independent shops. Surprised that a dealer would work on same principles.
Obvious question - when engine stalls does it happen at similar times, i.e. stopping at traffic light after driving on the highway for X number of miles, cold engine, rain, etc.
Is your Check Engine Light ON? If CEL is on, you can take your vehicle to an autoparts store and borrow their coder reader. This will read error codes stored in the computer. It would help to know if PCM (power control module) detected errors in certain areas and what they were. Now, here is a kicker... Even if CEL is NOT ON, you can still have some codes stored in the computer. I'd try to check them and see if there is anything there.
If you do pull any codes, write down ALL THE NUMBERS you see on the screens. Look for Engine load, Open/Closed Loop, Fuel Trims, etc.
If you you don't have any codes, check the the code reader is capable of reading live data form the engine. In that case pull data at idle and when you rev up the engine say to 2-2.5k RPM. Write down those numbers and post them here.

 

Thank you so much! I will get the codes. The engine light is on but it's been on for a while because I need a new catalytic converter.
It starts to stall at stop lights but it's not consistent. I'll try to pay more attention if it happens after a certain amt of miles, cold, etc. I really appreciate Kate the feedback!