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Discussion Starter #1
Hi, bit puzzled by this at present. My Laguna idles fine, sounds fine, has had all new plugs, leads etc.... and runs pretty well in urban use.

However take it onto the faster roads and it really struggles to respond and struggles up large hills to the point that it almost stops!

Any ideas, Im assuming CAT is ok as MOT test was passed without issue?

Rgds:confused: :confused:
 

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It could be one of many things causing your problem,so first some questions!:)

Does the engine seem to rev without the car going any faster?

Do you have any warning lights appear when the car plays up?

Does the temperature gauge fluctuate at all?

And finally,has the fuel consumption dropped recently?

:)
 

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Discussion Starter #3
Hi, thank you for your response and sorry it took me so long to reply!

1. No the engine does not rev without speeding up

2. No warning lights at all

3. Temp gauge doesnt fluctuate (though heater is cold but assuming this is a seperate issue ?)

4. No obvious increase in fuel consumption

Any ideas will be gratefully explored as at 5 mph uphill I do upset other road users :d
 

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A few things which may be causing your problem : not enought fuel , not enough air , partially blocked exhaust.
Not enough fuel : fuel filter patially blocked , fuel pump ineffective.
Not enough air : restricted air intake or dirty air filter.
Partially blocked exhaust : catalyst most likely area to get restricted.
Is there any misfiring when the loss of power occurs?
Also , did the problem suddenly appear or has it gradually got worse?
 

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Discussion Starter #5
Thanks Gadget

No it seemed to suddenly get worse but there is no misfiring, no lurching and running around town seems fairly happy, though not too responsive when you try to accelerate hard.

It has just had MOT so wouldnt CO2 emmisions been all over the place if an CAT problem?

The air filter is new, maybe the fuel pump/filter maybe a good place to start, any suggestions on how to test?
 

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Cat or exhaust could still be partially blocked and get through an mot. difficult to test though without a vacuum gauge.
Fuel system can be tested by checking delivery or pressure. Pressure test will require a gauge but delivery can be checked by disconnecting fuel pipe to fuel rail and running it into a vessel. (beware pressurised fuel spilling out)
If the lack of power is due to fuel shortage the engine will run weak as the ecu cannot compensate for it. (whereas lack of air the ecu just puts in less fuel) The lambda sensor would therefore stay low when the lack of power occurs. (should normally toggle up and down) This would normally generate a fault code and illuminate a warning light. (although some older ecu's dont do this)
 
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