I have a 99 dodge 1500 318 motor auto trans w overdrive. i have a slight miss when sitting at an idle with a warm or cold engine. it also misses when the engine is lugged. but not when i open the throttle and get the rpms up. i have replaced plugs, wires, rotor, cap, idle control valve, and air cleaner. im outa ideas please help

Codes?

check engine light isnt on, could it have a code even though the light isnt on?

yes

Ok, this might be a dumb question but how do i check for the codes? can i use the same code reader that i would use if the engine light was on?

Miles on the truck and does it ping under load ?

99,500 miles and no ping.

last time for a tune up ?

i put plugs, wires, cap, rotor, changed oil and air cleaner, and put an idle control valve in last week. i got the good stuff too, none of it was bargain discount walmart stuff. that was all in effort to try to get rid of the miss.

Battery and charging system checks out ok at idle?

I have a simlar problem with my 99 p/u , but it not as bad! any info would be a big help.. Someone mention it might be a vacuum leak..

it might be that the crankshaft position sensor (CKS)
is not picking up one of the notches on the flexplate
because the CKS is mounted just a few thousandths
to far out, or the plate is wobbling, etc

The CKS sensor is a pain to get to
so it might be worth using an oscilloscope
to monitor its electrical pulse train first

sometimes using an inductive pickup timing light
and clipping onto each cylinder in turn
will show which cylinder is the one missing

cylinders 7 and 8 in the back of Magnum engines
are prone to both head gasket and plenum gasket failure problems, plus their fuel injector baskets are 'first in line' on the fuel rail and fill with crud.
suspect them first

good luck

charging system is working great, i thought bout a vacume leak too. as far as i can tell there isnt one at idle, i used a piece of gas line as a stethoscope and there was no hissing.

i never thought bout the CPS, one question though, was is an oscilloscope and where can i get one. i never thought bout the timing light either. well thanks for the ideas, its back to the garage.