'03 1.8 122BHP Lumpy idle

[keithyboy]

Having surprised us by passing its MoT with a minimum of drama, the bloody thing has developed a lumpy idle.

It's fine when it's cold, and mostly fine when it's fully up to temperature, but when it's not quite warm the idle is very rough. It clears as soon as it is revved there are no misfires elsewhere in the rev range.

I have a new OBDII reader on the way but the engine check light isn't on.

I'm going to clean out the throttle body and ISCV and chuck a set of plugs in but any other thoughts?

[stuartrf]

Is it a gdi?
Take it down the motorway at 70 in 3rd clear it out abit

[keithyboy]

Originally Posted by stuartrf

Is it a gdi?
Take it down the motorway at 70 in 3rd clear it out abit

Used to do that with our old GDi (also took the intake off to clean which was a nightmare). This one is Volvo powered. I suspect a clean out of the throttle body and ISCV, new plugs, and a right good spanking might do the trick.

[skyship007]

Supermarket fuel up ??

[Robmac999]

Skyship, is that a question or a suggestion?
I never put supermarket fuel in my Volvo engined 1.8. All my previous cars were fine on it but my old S40 hated it and I got into the habit of Shell or BP fill ups. Never had a problem since.
The fact that's its ok when cold or hot could mean an iffy coilpack/ht lead maybe?
When you're doing the plugs you can inspect the coilpacks and leads anyway, but I hope that new plugs and cleaning of the throttle body do the trick.

[skyship007]

Just a question, hence the question mark in the title above my post.

I never touch Iffy fuel stations and stick to BP or Shell as much as possible. BP own Aral so I use them over here, unless I fuel up in Austria or Switzerland. When I do so, I just follow the crowd to some big fuel depot just across the frontier.
Some places are starting to change from winter to summer mix and that can then reveal an underlying engine issue, like coil packs etc. Hidden fault codes might reveal all.

[coffeejunky]

Could be a mixture of things.
I had a similar issue with the 1.8 Volvo engine in my sig.
The issue came about for a few reasons:
-Was running new but non-Volvo plugs. Changing the plugs helped an awful lot.
-Changed HT leads and replaced a cracked coil. This I suspect was the main cause of the lumpy running. Oil from careless oil top-ups/replacements gets down into the spark plug hole and seems to increase the likelihood of damage to the plastic the coils are made of causing small cracks.
-Ran a can of BG44K fuel system cleaner through it. This stuff really works! it helped a fair bit with smoothness.

Still can be a little lumpy on idle (nothing like before) so will be doing the following over Easter:
Clean ICSV fully.
Replace the fuel filter, not been done since we have owned the car and not sure when it was last done.

[Mount vision rider]

Was going to say could be something as simple as dirty or old plugs.

Skyship will be telling you to test your oil next!!!!! Hahahahaha

[keithyboy]

I've only been a passenger in it when it's been displaying the symptoms until this morning. I stuck some super unleaded in it and gave it a right good thrashing and it's a lot happier. New plugs should see it right I think.