my 96 ram is still misfiring on all cylinders. new cap n rotor, plugs, wires, ignition coil but nothing has fixed it. do i need a new timing belt/timing adjustment? ecm?

 

If it's misfiring on all cylinders then 1) the wires most likely are not connected to the correct location on the distributor cap, and 2) the wires are not routed properly. Read this TSB: https://dodgeforum.com/forum/2nd-gen...lug-wires.html

 

Could be clogged cat too. How does it run in general?

 

A couple things that come to mind are failing ignition coil, or weak fuel pressure, how does it run? What codes to you have?

 

Could be a failing coil or the coil wire is too close to a ground source. I once had some low RPM missing problems even with a brand new set of plug wires when the coil wire was touching the valve cover, I routed it up away from any ground source and the problem went away.

 

the wires are in the right position. i took them off and replaced them one at a time.

the catalytic converter is new from this last november

i just replaced the ignition coil last week.

i dont know the specific codes but i had a guy scan he said it was misfiring on all cyls and the down-flow o2 sensor was shot. could that be the problem?

it also "chugs" under load. if im in 4th and im going uphill it bounces. that and going about 50 in 4th it bounces. if i try to give it gas in 4th, it doesnt wanna shift up. i have to floor it to get it to shift up.

it seems to idle fine. it sounds nice. after it warms up for a few min it might rev up a small bit (it goes up and down every 2 seconds or so. less than 100 rpm difference, its just enough to notice.) it also seems like it has 2/3 of the power it should have. im guessing this is just because of it misfiring. just thought id throw it out there.

 

Double check the plug wire routing. Also, is the distributor cap mounted properly and not installed, slightly cocked at an angle?

 

i'll check the routing today but i dont think the cap is monted wrong. it was doing this before we replaced the cap. which is why we replaced the cap.

 

Are the heads original? If so, the stock heads are notorious for developing cracks.

 

This sounds more and more like a blown plenum gasket and it toasted the year old cat. And the downstream o2 has nothing to do with it. Most likely the upstream o2 is no good because of the plenum.