2002 spark plug issues and rough idle
I have a 2002 Ranger, supercab, 4.0 SOHC engine, A/C, Auto trans. with about 94K miles on it. I maintain with regular oil changes. Some time ago, check engine light came one and trouble codes read as P0171 and p0174, which means both banks too lean. Cleaned and checked MAF sensor, but these were fine. Went to a mechanic friend who hooked up this diagnostic computer he has which costs around $30k (can you believe that!) and told me I have a small vacuum leak somewhere. Nothing major, but enough to throw off the computer. He said possibility of the intake gasket between the manifold and the intake plenum, which he explained is a sort of "O" ring. He tried his test which is spraying water on it to find leak. (Hey! He's the mechanic!) Couldn't find leak. I suspect the vacuum booster for the brakes as as it looses it's 'boost' almost immediately upon engine off. Finances have prevented me from replacing it. In the meantime, engine has now developed a rough idle, and will sometimes stall when idling. A recheck of the trouble codes still shows same with lean mixtures on both banks. Auto parts store suggests replacing O2 sensors, but with 2 upstream sensors and 1 downstream (3 sensors total!) price of parts comes to almost $250! I hate to throw parts at it, if I don't need to! I ran some fuel injector cleaner through it, (some of the better stuff, not the 99 cent bottle) and no change. I wanted to change plugs but I can not figure how to reach the plugs on the pass. side esp. #3 with such a small gap between the A/C unit and the engine! I can't even get my hand in there! Is there a trick/method to reach #2 and #3 plugs? And what else could I check? I could call mechanic friend, but he lives quite a long ways away from me, and I haven't seen or spoken to him in too long. I hate to just phone him out of the blue and ask help when I haven't maintained contact with him for so long.