Hey everyone! I've posted this on a few different forums but have received little to no feedback, this forum seems a little more professional and active which is appreciated.
Truck is an 05' Rumble Bee with K&N CAI and cat delete and true customized duals all from the prior owner. I purchased the truck in April with 50,000 on the odo. Truck wasn't local so I couldn't take it to my mechanic and it was during heavy rain both times I test drove it. Realized it was pretty loud but the owner said it was due to the shorty mufflers so I didn't realize it was a cat delete till after I bought it and it started throwing cat efficiency codes, so I installed the spark plug defoulers and stuffed them with steel wool and eliminated codes and all was well for about a month, then it started surging around 27 mph under light acceleration and then I noticed it around 57 mph but mostly while the engine was cold. It surges and I have to let off the gas and to get it to quit. During the time it has different sound and feel, it actually has a raspier sound (cackles) and when it does it while at cruising speed, it surges until it tapers to cruising speed (with the raspy sound) then lerches or stutters till I let off the pedal? freaks me out and my wife refuses to drive it. When it's wet from rain out or on gravel it'll fish tail and I'm afraid of what it could do in the snow. It's throwing no codes and the cel does not come on? I've replaced the egr valve being one of the cheapest steps first, cleaned the throttle body, checked the pcv did a cold reset after the egr install, checked the plugs ran a tank of sea foam. Dealer won't touch it as it's a cat delete and it's not throwing codes. The general shop doesn't know where to start. I've done a accelerator pedal reset already. Could it be that I need a replacement throttle body as it seems to me that the surge may be from it opening when it shouldn't? HELP!

 

Have you thought about putting Cats and O2 sensors back on?

I mean it's kind of hard for the engine to accurately adjust for air and fuel without Oxygen sensors, or without correct readings.

Honestly I think that not having the O2's working properly/at all you may be masking up some other problems.

If there isn't enough back pressure you could have burnt a valve...?

It's really hard to tell what it might be... do you happen to have a video of it happening or anything?

 

I'll try to capture it on vid. I am already thinking about buying 2 Flowmaster catalytic converters and plugging the 02 sensor pig tails back in. Maybe I'll step up that process and order them sooner. Thanks for responding so quickly!

 

yeah I think that would be a good first step.

And no problem, welcome to Dodge Forum btw!

Don't forget to update your "My Garage"

 

Well installed my flowmaster high flow cats and did a cold reset of the ecm and the truck still surges? feels like the throttle body opens and I then have to abruptly let of the gas and then reapply the throttle. I cleaned the iat, but still get a feeling the problem is still somewhere between the iat and the throttle body. Still no codes and I cleaned the throttle body already. Should I try and replace either or both? why no codes?

 

Try to get this problem on video if you can...

If you can borrow or rent a code scanner that will let you datalog the sensor in the truck that might be a good idea too....

 

I'm thinking about taking it back to the dealership now that I have cats installed and just having them reflash the ecm since they sadi they wouldn't till I had them installed. I bumfuzzeled since no cel and no codes through all of this.

 

Had the ecm reflashed, the tech said it was behind by three updates, so now I have replaced the egr valve, the throttle body, cleaned the AIT, replaced the 2 forward 02 sensors, installed 2 new flowmaster high flow cats, checked plugs, checked for any vacuum air leaks around throttle body, performed the throttle sensor reset, and had the ECM reflashed and it still surges as if I'm giving it a quarter more throttle than I am during normal acceleration, till I let off the pedal. When it tops out during the surging if I let it, it lurches and stutters as if fuel starvation so I just ordered a new MAP Sensor and will install it when it arrives in a few day. When looking at the MAP Sensor I noticed it had the two mounting holes that showed wear from a previous installed sensor that must have been the original stock sensor. It looked like the original was the type that mounted with 2 bolts on either side but now it has the cheaper push in type? wonder why a truck that had less than 50k on the odo when I bought it in the spring would already have had the original map sensor replaced? and why wouldn't they replace it with the type that came stock? is there any difference between the 2 MAP sensors? Throughout all of this, the truck is not throwing ANY codes and no cel. no rich smelling exhaust and happens mostly while cold but still happens but with less frequency when warm.

 

what's the difference?

 

You want the Original OEM MAP Sensor..... do not purchase aftermarket, as they generally have different resistance values which has to be readjusted in the PCM manually.

So go to the Dealership and spend the $ for the right sensor.

If the same problem is present After you install the new MAP sensor and reset the PCM (by taking the Negative Terminal off at the battery and pumping the brakes a few times) then you know the MAP sensor isn't the problem and you should be able to return that MAP sensor to the dealership.

I'm still skeptical that this is a PCM issue, instead of a Transmission or Powertrain issue.... but again these are one of those problems that are very hard to diagnose over the internet.