P38A Help with P38 rough running 4.0 V8

S

Sophia2007

Member

Posts

27

• Nov 28, 2018

• #1

Hi all

I need some help with my 2001 4.0 V8 LPG rough running.

When it is cold on petrol it lacks power and pops and bangs when trying to accelerate, when it warms up a bit this problem passes.

Then when you are cruising between 40 and 60 it misfires you can feel a juddering where it is not running smoothly, to compensate i tend to accelerate and slow so i am speeding up and slowing down constantly to avoid the juddering. This problem happens on both petrol and LPG running.

Plugs have been changed using good Magnecore leads any ideas what is causing the problem it is getting rather annoying now.

Thanks

 

wammers

No longer with us, RIP

Donater

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58,170

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Preston Lancs.

• Nov 28, 2018

• #2

Reminds me of a Tom Jones song. "It's not unusual". Get some diag on it.

 

S

Sophia2007

Member

Posts

27

• Nov 28, 2018

• #3

Ok can you recommend any software i can buy online for Diagnostics?

 

Datatek

Well-Known Member

Posts

45,017

Location

Near Poitiers SW France

• Nov 28, 2018

• #4

Sophia2007 said:

Ok can you recommend any software i can buy online for Diagnostics?

Click to expand...

Blackbox Solutions Nanocom. Not cheap though.

 

wammers

No longer with us, RIP

Donater

Posts

58,170

Location

Preston Lancs.

• Nov 28, 2018

• #5

Sophia2007 said:

Ok can you recommend any software i can buy online for Diagnostics?

Click to expand...

Good OBDII set should read your engine. Won't do anything else though. You need Nanocom for the rest and for full fat engine diag.

 

Grrrrrr

Technician, Bodgit & Scarper Ltd

Full Member

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19,307

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Buckinghamshire, UK. ('95 DT)

• Nov 28, 2018

• #6

Hmmm, @Saint.V8 has experience of rough running v8s ...

 

Henry_b

Think outside, no box required.

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15,509

Location

somewhere else

• Nov 28, 2018

• #7

'Ave a look at the Coil packs

Could also be the CPS playing up

 

Last edited: Nov 28, 2018

Mark Piercy

Well fumbled member....

Full Member

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12,659

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Sud ouest France !

• Nov 28, 2018

• #8

Did it have the same problems before the plugs and leads were changed?
Have you checked to see if any vacuum pipes or air pipes have become dislodged?
Is there an engine warning light?

 

calguy

Member

Posts

34

Location

Redwood City

• Dec 8, 2018

• #9

+1 on checking both coil packs. I kept having a misfire on cylinder 7. Changed the spark plugs (#7 was burnt) and wires but kept misfiring. Then I checked the spark on #7 comparing it to #1 and it was very faint. Ended up replacing both coil packs and now all is good. Mine is a petrol not LPG though.