This has been going on for quite some time now, but is starting to annoy me.

When under heavy load, like driving up hills at 60mph in 4th gear and wearing heavy shoes on motorways, I get a sudden drop in power at about 3200rpm. Pushing it harder has no effect at all, but easing off and then re-accelerating seems to clear it for a while at least.

The drive to work features one large hill, and I can predict to within 10 metres where the power's going to drop off on the way up each side. It does it every day.

I've recently changed the air filter, and it hasn't improved.

Any thoughts what would cause this? All the other posts about similar problems seem to involve turbo issues, which of course, I doubt I would have.

This has been going on for quite some time now' date=' but is starting to annoy me.

When under heavy load, like driving up hills at 60mph in 4th gear and [b']wearing heavy shoes on motorways[/b], I get a sudden drop in power at about 3200rpm. Pushing it harder has no effect at all, but easing off and then re-accelerating seems to clear it for a while at least.

The drive to work features one large hill, and I can predict to within 10 metres where the power's going to drop off on the way up each side. It does it every day.

I've recently changed the air filter, and it hasn't improved.

Any thoughts what would cause this? All the other posts about similar problems seem to involve turbo issues, which of course, I doubt I would have.

not quite getting that phrase there mate care elaborate (sp??)

does this happen when not driving up hills?

lots of cars can suffer from 'flat spots' thats basically where somewhere in the rev range the power drops right off... this might be exacerbated by the hill making the problem obvious... so backing of the power then applying it again would effectivly take the car out of the flat spot and back to where there is power... quite why its doing this i dont know but someone might... but heres a couple of ideas:

petrol pump fighting gravity to pump petrol to the engine effectivly starving the engine creating a power 'flat spot'

cltuch slip ?

Joel

It's probable that the cause is your clutch.

If on highway you can see that RPMs go up but no acceleration... time to get a new one.

not quite getting that phrase there mate care elaborate (sp??)

Heavy shoes make the accelerator pedal go down further.

does this happen when not driving up hills?

On motorways' date=' when cruising along at a steady safe speed for the conditions, it'll do it seemingly at random. It's only when the engine's under a fair bit of load that it does it. Going up the same hill at 3200rpm in 3rd is no problem, but is ever so slow, and I wouldn't like to sit on the motorway in 3rd for very long.

lots of cars can suffer from 'flat spots' thats basically where somewhere in the rev range the power drops right off... this might be exacerbated by the hill making the problem obvious... so backing of the power then applying it again would effectivly take the car out of the flat spot and back to where there is power... quite why its doing this i dont know but someone might... but heres a couple of ideas:

I don't think it's a flat spot. Surely I could push through that by accelerating harder. What happens when I push harder though, is that the engine gets lumpy and the revs start to drop.

petrol pump fighting gravity to pump petrol to the engine effectivly starving the engine creating a power 'flat spot'

Might explain the hill, but there's not enough oomph at 80mph on the flat to hold the fuel back. I suppose it could be a blocked fuel filter.

cltuch slip ?

It doesn't feel like that. And the revs drop when it happens. I'd expect them to rise if the clutch was slipping.

Thanks for the suggestions though.

The closest thing to it that I've felt before is when a vacuum hose had split and the extra air pulled in was confusing the MAF sensor and making acceleration sluggish.

Dirty throttle body?

Dirty throttle body?

What's the recommended way of cleaning that then? Does it need to be removed, or is there something to spray down the intake?

If you have a look at this thread, you'll find cleaning instructaions for the turbo model. The process will be basically the same for your car.

http://www.briskoda.net/forums/showthread.php?t=22537

Well. Today I tried the hill in 3rd and 5th, and it misbehaved in exactly the same way.

Then when pulling away in 1st in a car park, it refused to go over 2000rpm no matter how hard I pushed the pedal, until of course, I released it and tried again.

So I'm going to clean the throttle body, fit new spark plugs, and if that doesn't work, investigate the fuel filter and pump.

Can anyone suggest anything else to try before sending it to the garage if none of the above work?