Last time I filled the tank I put in a bottle of Gumout. I still have half a tank of gas. Can I put the Lucas additive in now if I fill the tank again? Someone also mentioned Seafoam. Have you ever used that? I had never even heard of it.

 

Took truck to Mitsubishi performance shop (son's friend's neighbor is the owner). He said a) previous shop probably didn't even check for codes when they did the tuneup; b) they overcharged me for changing valve cover gaskets by about $75-125; c) very possible the injector was already getting bad, and is now throwing a fit. He suggests checking the injector (I will take it to him in about a week) and going from there. While he has it, he will also check to see if timing belt needs to be changed yet. Said if he can see writing on the belt he will have me hold off on it. And went on to advise about what should normally be done and roughly what it would cost. I felt pretty comfortable with what he was saying and his confidence. So at least I think I'm headed in the right direction. I will update as work goes forward. Again, thank you so much for your help. Very much appreciated.

 

yes you can add the lucas

 

Update: Montero spent the morning at a Mitsubishi performance shop. He could not get it to run rough again at low outside temp. He drove it, checked codes, dove under the hood and checked everything out - PCM good, injectors good, connections good, clean. He thinks the prior shop had an injector plugged in loosely from tuneup, and when I took it back, they "inadvertently" corrected the problem while checking things out. It is only throwing the catalytic converter code now. He suggests O2 sensor before going after the converter - quoted about $150 for sensor replacement. He also changed the air filter - which the prior shop said didn't need to be done at tuneup, although they quoted their price to include it. Charge to check it all out and replace air filter $60. Wow. What a difference. It does need timing belt changed - I was afraid of that - so it goes in next week. Quoted $600 - replace timing belt and seals, timing belt tensioner, water pump. That happens next Wednesday. I have to say I have a much better comfort level with this guy - he explains everything in English and I don't feel as though he's wanting to dig into my pockets. He said, "I'm not going to replace things that don't need to be replaced, and charge you money you don't need to spend - that's not why you brought your vehicle in here." Anyway, maybe the info comes in handy for someone else with same problems - probably not, but who knows - and I want to thank you for your help with this issue.

 

wow cool and bummer and as always keep us posted the problem might show up again

 

Update: Montero now has timing belt, tensioner, seals, water pump (none of this had been done before - has 155,000 miles on it - sheesh). Still no more rough idle (whew). New tires this weekend, then next month on to change all fluids and investigate catalytic converter code. Shop owner says this is a good truck and good for another 150-200,000 miles with good maintenance. May just get this vehicle on a regular maintenance schedule yet! Thanks for all help, and am looking forward to enjoying my "new" ride for years to come.