2003 4.4 petrol 'stuffy'

Have a 4.4 2003, 62k genuine. LPG converted too. Drives so flat and gutless, either petrol or gas, doesn't matter. If I absolutely thrash it EML light comes on and quick scan says multiple misfire. Although it doesn't feel misfiring at all! Free Erving in neutral and it feels fine, but driving it it feels gutless and just won't go. I'm thinking blocked cat or cats?

Is the clutch slipping when you accelerate ?

What clutch? It's auto? Drives fine, as in fine but gutless. No clutch slip. To speak of

The BMW's fitted with the same engine (M62TUB44) suffer badly with blocked cats, not heard of it on the L322, but that is not to say it can't happen .

take the front lambda sensors out to make a gas path and see if she gains more performance .

As in torque converter slip !!

2.0_hippo said:

As in torque converter slip !!

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That doesn't cause a multiple missfire fault to be logged

Wonder if there's some dodgy wiring from the LPG conversion ...?

2.0_hippo said:

Wonder if there's some dodgy wiring from the LPG conversion ...?

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That's more like it. I remember there was another thread where the LPG wiring installation was to blame for missfires. Good stuff LPG.

Datatek said:

That's more like it. I remember there was another thread where the LPG wiring installation was to blame for missfires. Good stuff LPG.

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Good stuff L322's

Datatek said:

That's more like it. I remember there was another thread where the LPG wiring installation was to blame for missfires. Good stuff LPG.

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Yes

Didn't saint have issues with his at first ?

2.0_hippo said:

Yes

Didn't saint have issues with his at first ?

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Nope, my LPG install is spot on, and works well.....no engine issues thus far!! (Keeping them fingers crossed)

As i posted above, blocked cats are common on the E38 E39 and E53 BMWs the L322 is based on....common fault is misfires, lumpy running and a reluctance to rev beyond 3.5-4k....

One way to tell is if you have upstream lambdas is to take them out so the exhaust can exit via the sensor holes, if running gets better....the cats are blocked.

Another common one is the rocker covers leaking oil into the well where the plugs and coils are causing arc and tracking as the coil stems become contaminated....this is caused by crankcase pressure from a blocked PCV valve.

Thanks Saint. Will try further investigations. It is sooooo flat around 3-4k when under load. rev's free in neutral and no hesitations, but drive it up the roadand try kicking it down!! Nothing!

if you drive it in sprt mode and manually hold in gear, will it rev up then?

donp38 said:

if you drive it in sprt mode and manually hold in gear, will it rev up then?

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Not really, it still struggles. Should it make a difference then?

beanmasteruk said:

Not really, it still struggles. Should it make a difference then?

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Think he was trying to eliminate gearbox issues....