Just did some work to replace the head gaskets and clean the fuel injectors. Before I had codes for cylinder #6 misfire and a lean code from O2B2S1, and that was before I blew a head gasket. Now everything is back together and It runs great for about a minute then it idles rough and changes from high idle to low idle and repeats. Runs great on the road but as soon as it stop the rough idle starts. Codes I'm pulling now are for EGR valve closed or inop no flow detected and the O2 sensor reading lean again. No smoke from the tail pipe after running it 50 miles and I figured a misfire would be detected as well. I was thinking I left something unplugged, but everything is where it is supposed to be. The EGR system I don't have to much of a grasp on, so I'm not sure what to look for. I don't want to buy an EGR valve and the problem be something else.
3.8l Running Rough
- Thread starter TheChad88
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Dan_Soprano
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jozsefsz
15 Year Member
On my old 3.8, after the head gasket blew, it toasted the fuel injector in that cylinder too (I imagine the steam coming back out the intake valve). May be worth a look, but of course it could be anything else. o2 sensor also don't care much for being doused in coolant. You might want to change those, and check that #6 injector. The engine has to run a certain number of cycles before it will set a code for misfire.
I actually replaced all the bank 2 injectors during the head job with some good ones I had in another engine. I swapped the engine back in February and still had the old one lying around. All the injectors were cleaned out and re-sealed. I'm guessing the problem is the o2 sensor. My short term fuel trim is jumping up and down, and 3 of my sensors are ready 0.05-0.07 while b1s1 is reading 0.5-0.6. Dunno.
No the EGR has not been replaced. a friend of mine is telling me I need a new DPFE sensor?
No the EGR has not been replaced. a friend of mine is telling me I need a new DPFE sensor?
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jozsefsz
15 Year Member
Those commonly go bad on the 3.8's (the DPFE sensor), and will give you an 'EGR insufficient flow" type code. I've never known that to cause a driveability issue though so I don't think it will help the rough running. But who knows...
Oxygen sensors. Disconnected all of them yesterday and had no problems except for a hesitation when I opened the throttle which I kinda expected. Gonna start pluging certain sensors back in to narrow down the problem. I have a code for bank 2 sensor 1 but when I pulled the pre cat sensors the problem remained. And as I stated above I seem to have 3 that are reading off I think. Anyone know the reading they are supposed to have? I thought they were supposed to read around 0.5.
