My felicia fun had always had rough idle I have done everything mentioned on this forum throttle body with ecu reset temp sensor etc. a problem that is getting worse is burning oil whenever I go down a hill and accelerate when at the bottom I leave a cloud of blue smoke also have to top oil up every 3/4 weeks is this the seals gone as have heard this before could this be causing my idling problem is it easy to repair or replace engine I have a spare but have only drove 45mile in it so don't no it's realiability

Your description suggests the engine has worn piston rings. If you want to be 100% sure, you need to do at least a compression test (dry and wet).

If it burns oil all the time it will be the piston rings, if it only burn oil on the overrun like when going down hill its more likely to be the valve stem seals gone.

If it burns oil all the time it will be the piston rings, if it only burn oil on the overrun like when going down hill its more likely to be the valve stem seals gone.

Agreed, particularly with the reports of puffing smoke when picking up throttle.

Bryboi

In case you don't have access to a compression tester, do this: with engine cold start it and watch if there is blue smoke down the tailpipe. Then let it warm up at idle and see if the smoke fades out. When the engine is warm revv the engine hard repeatedly. Is there heavy blue smoke? If in doubt take a video and show it here. How many miles has the engine?

Thanks for the replies there was no blue smoke on startup or even when it was warm.I can't really say when it uses oil as it is my daily commute usually a 60mile round trip there is always some hills somewhere along the way. If it is stem or Pistons could that affect the idle

If it is stem or Pistons could that affect the idle

A rough idle is usually associated with bad compression. So the answer to your selective question is piston rings.

But in a broader analysis, there are other factors that could affect the idle too.

I take it Pistons and stem seals are a big job even if you have the right equipment. What would be price roughly if these are the problems. I have changed throttle body temp sencor are there any other things skodas are known for to cause idling problems

It is possible to change the valve seals with the cylinder head in situ, but it does take some specialist tooling to do it.

Lol that's me having a go out the window then. Any idea roughly what a garage would charge. I have got a spare engine but don't no if it's any good as when I brought it there was a can of stop leak on floor next to it is it worth a try.

"leak stop" products normally suggest coolant loss to me. This could suggest that the second engine has overheated, but there's no obvious way of proving that.

 

The only coolant related "leaks" you normally get from the block are around the water pump, the head gasket (most likely to have damaged the engine castings) or the core plugs.