My VOLVO 940 turbo is running rough. I have read that it may be a dirty idle air control and or throttle body. I would like to clean them.. Is it a tough job? Also is there gas treatment that might clean them?

 

"Running rough" - or a rough idle will not be caused by a dirty iac or throttle body, unless the idle is too low.

A rough idle is could be a cylinder misfire due to a lean condition - for instance a leaking intake manifold gasket can cause that.

The throttle housing should be cleaned on a regular basis of course since the pcv system dumps oil laden fumes out right in front of it.

There is no tune up in a can that will clean a throttle body - but a can of carb cleaner and a rag will.

 

As well as rough idle today after a ten minute drive smoke was coming out of the catalytic converter, any ideas why?

 

it takes a few minutes for the cat to heat up but you are either running way rich or you have some oil in the exhaust (bad rings, bad turbo seals can do that) and the cat finally got hot enough to burn off what had accumulated on its grid. What do your spark plugs look like?

 

I haven't checked the plugs, what should I look for? Also forgot, smoke is white no coolant odor.

 

Any codes?

https://www.2carpros.com/articles/vo...e-1983-to-1993

Smoking convertor is way too rich or lean, could be anything from misfiring due to an ignition problem to a fuel pressure regulator that's sending too much fuel.

 

Yes 1-1-3, also slight gasoline odor when starting.

 

Could be extremely rich - most complain of very bad gas mileage. I would check fuel pressure and check for gas in the vacuum line on the end of the fuel pressure regulator.

 

I bought an aftermarket gas cap. Could it be that is isn't quite tight that is causing the problem?

 

No. ..

 

Got the plugs out, so tight they seemed welded in. Tips are black and eroded to one third normal thickness.

 

New plugs and wires, the 477,000 mi. beast again running well. I bought the wagon from the 3rd owner and am slowly restoring it. Any advice how and where to find tan interior panels and tan seat covers will be greatly appreciated as is the advice currently given.