XU7JP4 engine idle problem (stationary only, not while moving)

[fruitnveg]

Hello PF folk,

I got a 2000 Peugeot 406 with the XU7JP4 engine in it and the idle's being a bit rough when it's stationary, but not while moving...

I tested this by driving along at 60mph on a straight road with a roundabout at the end, not far from roundabout I put it in neutral and the idle was spot on until the car stopped, then went rough, making me think it's possibly air related. I get nearly spot on MPG by the way.

When I say rough, it at worst goes +/1 150rpm, doesn't go over 1000 or come close to stalling at all - been there since I bought it a few weeks ago - sometimes it disappears completely.

I've had a little play around so far earlier and the MAP sensor and air intake tube had some oily grot which I cleared with WD40 but it hasn't helped. I'm not too bothered as it was cheap and still goes and I only want it for a year or so - just be nice to fix!

Any suggestions gratefully received - thanks!

[fruitnveg]

Forgot to add I'm going to try cleaning the idle speed control valve tomorrow.

[bettyswollocks]

Has it got a/c ?

[fruitnveg]

Originally Posted by bettyswollocks

Has it got a/c ?

Yep it's got A/C - all the pre mentioned tests have had A/C switched off. If you have the vehicle stationary, switch the A/C on and the lumpyness (when it's there) almost disappears when the compressor turns on.

[bettyswollocks]

Originally Posted by fruitnveg

Yep it's got A/C - all the pre mentioned tests have had A/C switched off. If you have the vehicle stationary, switch the A/C on and the lumpyness (when it's there) almost disappears when the compressor turns on.

I would be looking in this area , at the tensioners ,belts and pulley `s

[fruitnveg]

Originally Posted by bettyswollocks

I would be looking in this area , at the tensioners ,belts and pulley `s

Well a new set of spark plugs appears to have done the trick at the moment, will keep an eye on it for the next week! Thanks very much for your input.