Poor Car Acceleration

[Beswad]

I've changed the spark plug, air filter and added some fuel additive to clean the catalytic convertor in the hope to cure the problem but to no avail.

I notice on the motorway the acceleration is particular poor when I hit 50mph. The acceleration is very slow despite putting my foot on the throttle the engine just revs up to 4000rpm it takes awhile for the desired speed to catch up.

Can anyone suggest where I should invesitgate where the problem lies?

[Answerprancer]

If the engine is revving up and the car not getting faster it probably means your clutch is slipping - only happens to cars with high milage afaik.

[TWR]

Is the car getting the full revs? check the throtle cabe, are the plug leads connected? what CC is the car?

[scotman]

If things are as you describe then I agree with AP^

Do you know if your clutch is cable operated or hydraulic? If cable operated you need to check that there is enough slack in cable setting.

[SlackAlice]

Would be nice to know what car/year/mileage/engine size? Manual or automatic?

[TWR]

If the Clutch was slipping this would have been slipping locally apart from the Motorways.

[top_driver]

it doesn't always slip at low speed, usually if the rpm separates from the odometer then its the clutch slipping, the worse it gets the more it slips, try accelerating lightly or not as heavy it should stay with the revs, i'm assuming it is a manual car

[Beswad]

It's a Suzuki Ignis 1.3 manual. Current mile on the clock is 32k. I wouldn't think it's the clutch as the gear change seems to be fine base on my previous car experience on worn clutches. The acceleration is also poor when driving off from stationary in 1st & 2nd gear. I think I will have the clutch looked at very soon. Thank you all for your suggestions.

[SlackAlice]

Fuel consumption got worse? Any engine management lights on?

[Beswad]

@SlackAlice Fuel consumption is getting worse due to having to accelerate harder to get the car moving and no there isn't any warning lights showing. Thanks.

[TWR]

Have you checked under the car for a fuel leak? is there a smell of petrol?

[TWR]

Forgot to say, get someone to depress the accelerator pedal as you check under the bonnet if its working right.

[Beswad]

@TWR Will look into that is well. Thanks