Rough running, various trouble codes

[ferkle]

Hi

I'm hoping to see if anyone can shed some light. 

I made the potential mistake of buying a highish mileage cheap LS430 with issues, and I'm getting to the end of my tether. 

So, long story short, the car runs absolutely spot on for the first 10 minutes when the engine is cold. Loads of grunt, smooth as you like, happy days. 

Once the car gets a little warm, and goes into what I will assume for now is closed circuit running, its gets rough. 

At idle in D the large sputters and lurches and is lumpy as holy hell. 

In driving it feels like its running on around 3-5 cylinders until you give it a good old kick in the pants and get it revving and feels/sounds like cylinders are being lit as the revs build. Like the engine is slowly coming to life/waking up

If I manually shift around the box and keep the revs up over 2000rpm  it settles down and becomes a delight again. 

Now for the list. 

P0300  - random misfire

P0301-0308 - I'll get codes for a few different misfires on any/all cylinders, usually 3 or 4 stack up between resets. 

P0141 - O2 sensor heater circuit malfunction in bank 1 sensor 2 - this has been replaced, and the code persists

P0171 - Bank 1 too lean

P0601 – Engine control module (ECM) -memory check sum error

P0003 - Fuel Volume Regulator Control Circuit Low

P0101 - Mass Air Flow Sensor Circuit Range/Performance

I also regularly get the flashing MIL lamp, but not in consistent driving conditions, i.e. can happen on light throttle cruising, heavy throttle acceleration or anything in between, usually only for a few moments. 

So, what have I done to try and sort these? 

Naturally, i assumed misfires = weak spark etc, so plugs and coils have been changed. No change. 

I was seeing the 0141 code a lot, so changed B2S2 O2 sensor. No change. 

I found an earth strap broken and connected to nothing under the car when changing said O2 sensor, so have replaced. 

I've cleaned the MAF, which was quite dirty, and seemed to smooth things out a little, for a short time. 

So yes, I'm at a loss! Anyone have any ideas before I consider drastic action?! 

Thanks

[Bluesman]

When I had what you describe it turned out to be the Oxygen Sensor on Bank1 I had both changed and she has never missed a beat since.

[messi]

Hi there 

Okay, first thing I think it might have something to do with the fuel filter, maybe it's clogged up, maybe previous owner always let it go down to reserve and used rubbish supermarket fuel which has clogged it up. Let the fuel go almost empty, then refill using shell v power and drive around a good few miles to clean the rubbish out. See if that helps. If it doesn't then it could be all 4 o2 sensors.

[steve2006]

The fact that the engine runs fine from cold and then has problems after 10 minutes would suggest something is breaking down when it has warmed up.

Given the timescale,symptoms and fault codes I would be looking at all the O2 sensor outputs as these are susceptible to thermal effects but I would also check the signal output from the CPS as this is another part that can be affected by heat and vibration.

You really need the correct diagnostic equipment that will show live data from these sensors to confirm they are working or not.

[TigerFish]

The fact it runs ok when cold does tend to push it towards the O2 sensors. They don't do anything until the engine is up to temperature. I'm not quite following which O2 sensors have been changed, You mention code P0141 B1S2, and has been changed, then mention B2S2 has been changed. Does that mean both S2's have been changed? For generic sensors, or genuine, or non-genuine but correct connector plugs?

 

[ferkle]

49 minutes ago, messi said:

38 minutes ago, TigerFish said:

The fact it runs ok when cold does tend to push it towards the O2 sensors. They don't do anything until the engine is up to temperature. I'm not quite following which O2 sensors have been changed, You mention code P0141 B1S2, and has been changed, then mention B2S2 has been changed. Does that mean both S2's have been changed? For generic sensors, or genuine, or non-genuine but correct connector plugs?

 

That's my typo, only B1S2 has been changed so far. 

Happily I have the other 3 on hand, and they are all genuine. 

Cheers. 

[ferkle]

43 minutes ago, steve2006 said:

The fact that the engine runs fine from cold and then has problems after 10 minutes would suggest something is breaking down when it has warmed up.

Given the timescale,symptoms and fault codes I would be looking at all the O2 sensor outputs as these are susceptible to thermal effects but I would also check the signal output from the CPS as this is another part that can be affected by heat and vibration.

You really need the correct diagnostic equipment that will show live data from these sensors to confirm they are working or not.

Thanks, yes, I had considered both Crank and Cam sensors. 

I've been meaning to get a techstream laptop set up, but things keep getting in the way. Closest I have to live logging at the moment is Torque on Android. 

[ferkle]

Alright then. Fingers crossed we're all sorted for that. It seems I had a dud O2 sensor which has been swapped out now. So far, so good. 

 

Thanks very much everyone. 

 

(Now to sort the LPG and get that to run right, but that's for another day!)

[TigerFish]

good result