Hi,

I have a 98 Ram that has had a persistent problem since I've owned it (1 year). When I start it up, all seems well, however after about two minutes the following happens:

The engine starts to idle VERY rough-sounds like it want to choke out
There is a huge air sucking sound coming from the intake area of the plennum
The exhaust smells very bad - like it's burning very rich
It almost want to die but doesn't quite
After it warms up it runs fine

I've replaced the IAC and the TPS

I took it to a auto parts store and had them read for codes when the check engine light was on (now its not) and this is what the codes read:

P0452 EVAP
P0410 Sec Air Injection Pump
P0507 IAC

I'm confused because I did replace the IAC and the TPS and reset the computer, yet I still have this issue. And does this truck even have a smog pump?? I can't find one.

Any thoughts?

 

Sounds like you've got a bad cat. Like hey you suggests, take out your front O2 sensor and try again to see if it does the same thing. The high backpressure makes it hard for the engine to keep running. It probably is able to clear up enough to drive once the cat is VERY hot...does it seem real low on power?

Alternatives: Bad Plenum gasket, Bad front o2 sensor(doubtful by your description) A bad PCV valve could cause the engine to run very rough thought not exactly as you describe.

Check all your plastic vacuum tubing for breaks (be gentle, they are brittle with age) pump your brakes a few times to see if that makes a big difference in your start up idle...if it does you may need to reset your computer again.

Theres more but start with the basics...

 

Sounds like restricted cat exhaust flow. If it is clogged then most likely your plenum/intake gasket needs attention. It's like a milkshake with a big strawberry stuck in the straw.Your IAC is sucking it's brains out.

 

I don't think there even is an air injection pump, unless you have the V-10 (maybe) or, the HD 360.

Disconnect the front O2 sensor. Take the truck for a drive. Any better?

 

i have a 2005 dodge dakota 4.7l 4x4 running rich and rough have to disconnect the little hose that goes into the throttle body in order for it to stay on..if i connect it it will turn off.....when running the truck it smells like fuel and feals like it has a short somewhere and loses power and sometimes power is perfect....after each start it high idles and a while it goes back to low idle..

 

Wrong forum. Post in the third gen Dakota section.

 

if all this works and you still get the sucking sound, check your filter box gasket, I had to and it makes a huuuuge difference lol

 

any updates on figuring out what this was? this is exactly what my truck does. isnt neccesarily as constant as you seem to be having, but the same problem. lately it seems to be warm or cold if you let it idle at a traffic light for more than a minute itll do this. rough idle and huge sucking noise. you have to rev it up and get it back up to power otherwise when you try to go itll just pop and putter and wont go anywhere at all till it eventually catches and then power surges back

 

I was having this problem (and am still in the process of fixing it thanks to a stuck o2 sensor in my pipe)....mine turned out to be a faulty front 02 sensor...when I unplugged it, the rough idling and sucking sound went away immediately

 

yeah think thats my problem too. p/o had the cat changed on the truck and instead of two theres only one lol but i got under there last night the front o2 sensor whoever installed it plugged it in and then tightened it in so the wires got all twisted up and are all frayed