Reader Question: Hello,
I am not sure how this works but I did fill out the insurance quote info. Anyhow, I have a 1991 Mitsubishi Montero LS 3.0L with 130,000 miles on it.
For about 4 years, I have been trying to fix it or have it fixed and so far no luck and I am running out of patience. It used to be a good reliable car but now I cannot even sell it to pay my son’s $1,600 orthodontic bill. At first, it idle real rough and sometimes died when I accelerated.
I have had it at two mechanics for timing and replacement of the Mass Air Flow (MAF) sensor (ouch). It didn’t change anything. Now I can start it with the MAF unplugged and it will start right up, idle well, and respond when I give it gas.
With the MAF plugged in, it idles rough and fluctuates eventually dies. I thought it might be a clogged cat so I unhooked the cat and still no difference.
What the heck do I do? No one seems to be able to fix it and I am running out of options.
Please, please help.
I feel your pain! I am not sure how much help I can really be over email. Usually, usually when you can unplug the MAF sensor and the engine runs better the MAF sensor is faulty. Since you already replaced it and nothing happened…hummmmmm.
I would first make sure you do not have a vacuum leak under the hood somewhere. Make sure to look under the hard plastic hose between the air cleaner and the throttle body of the engine. I would also clean the throttle body and idle control motor.
If you do not see anything wrong there, next step would be to manually test the fuel pump pressure at the engine with a manual pressure gauge. I want to rule out the possibility of a weak fuel pump.
Last thing to do is hook up a hand scanner to your onboard computer and see what the computer is seeing. I would start with checking the oxygen sensor readings and go from there.