Chrysler Repair: 1998 dodge ram 1500 5.9l 360, dodge ram 1500, wd 40

Question
my truck runs good for a while it would start hunting at an idle after it sat and idle for a while  then in the last month the truck would drive fine then all of a suddeen it would lose power and hunt and if i accelerated it would sound like the intake was backfirrering no codes so i cleaned the intake and as i was cleaning the tps code came up i put new one now no code but truck still acts the same so i put a new idle air control motor and still doing the same would the intake gasket possibly cause the problem?

Answer
Hi Ray,
Sure, an intake manifold leak can play havoc with the idle, and you can check for that by using a spray can of starter fluid. Spray extremely short bursts from a straw, so as not to cause a fire, around the edge of the intake manifold while idling to notice any point where there is an unusual change in the idle rpm.
One my favorite culprits for rough idle is the egr valve. If that has a sticky stem it can remain ajar at idle when it must be closed tight for a steady idle situation. So look at that valve stem, which has slot into which you can insert the tip of a screwdriver, move the stem back and forth and notice if the internal spring-action is firmly moving it to a dead stop on it own accord. If not, then spray the stem with WD-40 and work it back and forth some more.
Of course, keep checking for fault codes. You might want to also check the wiring associated with the tps/ais as it can get melted from the exhaust manifold heat which could also cause the hunting that you are describing.
Please let me know if you find a solution. You can use the "thank and rate" tab to get back easily, where you will find a comments section to tell me.
Roland