1998 Ram Van 3500, 5.9L
I’m currently 2600 miles deep into a roadtrip. the first 2000 miles went smoothly, with the exception that, at around 1000 miles in, I noticed the van feeling/sounding boggy on hills and needing a lot of pedal. So, I suspected the catalytic converter might be restricted. I whacked it with a hammer a few times and all the power returned. No more bogging. Yay! I figured I’ll have a new cat installed when I get back.

however, a new problem cropped up in the past 700 miles or so, which is that a sudden loss of power turns on like a light switch. What I mean is, I’ll be cruising along at 70 mph with no problems, everything sounding great, and feeling great and then all the sudden, the power just shuts down and the vehicle bogs and if you push on the pedal, it just bogs more and will slow down to zero. if I pop it in neutral, it idles fine, but if I touch the pedal it feels like it’s starving for fuel.

if I pop it in neutral and coast to a stop, the engine will stay idling, and if I wait for about a minute, I can drive normally again. So far, it’s happened four times in the past 700 miles, with shorter and shorter duration between episodes. At this rate, I’m not sure if I’ll be able to make it back home without repairing this.

when it happens, there are no check engine lights, all gauges are normal, voltage, water, temp, oil, pressure, transmission temperature all look normal. I’m suspicious of either the fuel pump or the PCU. Any thoughts? Sadly, I left my backup PCU at home which in retrospect is a really stupid thing to do. My reasoning was that I already have so much crap inside of the camper that I didn’t want to bring unnecessary things and I thought that worst case scenario if I was left stranded, I would just have the ECU FedExed from home.

if anyone else has had this occurr, I would appreciate your input.

 

Try whacking on your cat some more. If it is melting down, that could account for some of your issues. If you have a scanner, what are your long, and short-term fuel trims doing?

 

Thank you, I’ll try some more whacking.

I don’t have a data scanner. Are you referring to one of those Bluetooth OBD2 dongles? Maybe I’ll grab one today from an auto parts store.

 

Need software to go with the dongle though, and most I have seen isn't worth the money. Even if its free.....

 

Do you recommend a scanner? Something they sell at oreilly, ideally since that what’s by my here in the middle of nowhere. Should I grab a hand-held one?

 

Out of curiosity, does that look like a factory catalytic converter?
To me, it looks like it’s been welded in after the fact.

 

I use Torque Pro -- its OK

 

so I wrapped on the catalytic converter a little more with a hammer. I can hear the honeycomb pieces rattling around in there ever since the first time I wrapped on it with a hammer.

I’ve only driven it about 60 miles since the last post but so far the problem hasn’t come back. I posted a couple of fuel trim readings from cruise control at about 70 mph mostly flatland.

 

To me it sounds like the issue is with the catalytic converter. The second possibility is a failing fuel pump not delivering enough volume during engine loads.

 

If the cat rattles, yep, that's a problem. It DOES look like it was welded in at some point... but, it follows the stock design. (dual in, single out, O2 between in pipes coming in?)