Hi everyone.

I have a 1998 Felicia lxi 13mpi, only done 23000 and for a while it has been running rough at idle, like it is only running on 3 cylinders, and there is a slight hesitation when you first hit the gas. there was also a problem with the coolant sensor(which i replaced). It is now MOT time and had to replace the back section of exhaust, (the other looked ok on the outside but was full of rust rattling around inside).

Failed MOT on "exhaust emissions carbon monoxide content after 2nd fast idle excessive " and car is still running rough at idle.

Can anyone please help.

Have you tried to adjust the valve clearences? It may help with emissions also.

No this has not been checked, will check it now though. Thanks

i bought my 99 felicia 1.3 mpi about 6 months ago now and its always had a really rough idle then when it broke down and i replaced the ecu with one i got off ebay its still got a rough idle but now its at like 600 rpm ish and my battery arning light flickers all the time when its idle, i adjusted the throttle earlier to try and make it rev higher bu still got the same problem :S

Turned out it was an inlet manifold air leak, changed the gasket and the car instantly ran smoother, no more uneven feeling in the car and no more chug chug out of the back end. Hopefully this has solved the emissions problem, taking it back for mot retest this week and will post the outcome soon.

Also try spraying some carb cleaner near the manifold, if the revs rise you have a gasket gone.

Also try spraying some carb cleaner near the manifold, if the revs rise you have a gasket gone.

Cool tip!!! :P

throttle body needs reseting/adjusting

I have the same problem... but it will run very smooth while cold... but once its warmed up it becomes a bit rough.

Which is the inlet manifold... is it under the throttle body?

I have the same problem... but it will run very smooth while cold... but once its warmed up it becomes a bit rough.

Which is the inlet manifold... is it under the throttle body?

Yes, the silver one with the pipes coming off it - looks like 4 tubes moulded into one, behind the cam cover & under the air filter/throttle body.

The other possibility for this sort of problem is a failed HT lead.

Or coil pack in MPI?

I have the same problem... but it will run very smooth while cold... but once its warmed up it becomes a bit rough.

Which is the inlet manifold... is it under the throttle body?

Aha so i am not alone in this. Mine is smoother when cold also which seems to confirm that it is an inlet manifold issue. I have two gaskets on order from skoda dealer at the price of £1.29!!! :eek:

Here's an idea why don't all who have this problem try changing the gaskets as it looks a fairly straightforward job and then report back here on this thread to see if there is any difference? This will help resolve things a bit more

thanks to everyone by the way who had suggestions on my previous similar thread:thumbup:

if it's a hot/cold issue trying unplugging the coolant temperature sensor to see if that makes any difference

Just had a tinker around under the bonnet...

Took the fuel body off to check out the gasket and it was split and very squashed and degrading... so ordered a new one from skoda garage... Can't believe how much its going to cost me.

159!!!.... Pence!!!! hehehe

Also clean the rubber seal between the air box and throttle body as it wasn't seated properly.

I also re-adjusted the throttle cable as there was some slack in it.

So will report back after the gasket change.

Just had a tinker around under the bonnet...

Took the fuel body off to check out the gasket and it was split and very squashed and degrading... so ordered a new one from skoda garage... Can't believe how much its going to cost me.

159!!!.... Pence!!!! hehehe

Also clean the rubber seal between the air box and throttle body as it wasn't seated properly.

I also re-adjusted the throttle cable as there was some slack in it.

So will report back after the gasket change.

Right i have also got the throttle body gasket for £1.59 along with inlet manifold gaskets. Will try changing the throttle body gasket first this weekend then if no change the inlet manifold gaskets. My idle is sticking now!!

Fast idle speed (as in initial warm up speed, as if the choke is applied in a carb car) is about 1000 rpm. If the idle speed does not drop down to 700 approx. after a few minutes (depending on the outside temperature), the engine temp sensor is probably on its way out.

If im going to be changing the gasket just under the throttle body to fix this problem should i also change a gasket thats on the inlet manifold?

Is there two on it? or just the one at the top end?

Is it hard to do... sorry don't have my haynes on me to check.

If it's similar to the single body ZX, the spacer/insulator under the throttle body is a completely different type of unit (plastic or rubbery stuff) to the manifold to head gasket (usual thin gasket materials).

If im going to be changing the gasket just under the throttle body to fix this problem should i also change a gasket thats on the inlet manifold?

Is there two on it? or just the one at the top end?

Is it hard to do... sorry don't have my haynes on me to check.

Not sure about SPi but on MPi there is a card type throttle body gasket and two card type inlet manifold gaskets. Cost a few quid

Fast idle speed (as in initial warm up speed, as if the choke is applied in a carb car) is about 1000 rpm. If the idle speed does not drop down to 700 approx. after a few minutes (depending on the outside temperature), the engine temp sensor is probably on its way out.

Thanks, i hope it isn't knackered as i put a complete new thermostat body and sensor on about a year ago!! I think my old one is somewhere in my toolbox so i will try this. Fuel economy is still ok though averaging around 40mpg but the temperture stick seems to fluctuate a little bit between the half way point. The idle sticks at anything between 1000rpm and 1500rpm and at other times it falls normally to 800rpm, although 1000rpm seems the norm at the minute and getting worse!!

Thanks, i hope it isn't knackered as i put a complete new thermostat body and sensor on about a year ago!! I think my old one is somewhere in my toolbox so i will try this. Fuel economy is still ok though averaging around 40mpg but the temperture stick seems to fluctuate a little bit between the half way point. The idle sticks at anything between 1000rpm and 1500rpm and at other times it falls normally to 800rpm, although 1000rpm seems the norm at the minute and getting worse!!

I was going to edit the post you quoted to add that it could be something else too like the throttle body gasket or the throttle valve positioning module/idle switch or the air pressure/temp sensor on the MPi

Right time to report back on my 1.3MPi simos throttle system.

Changed throttle body gasket, changed temp sensor, cleaned throttle butterfly, tightened inlet manifold nuts, adjusted tappets, checked every pipe going into throttle body, cleaned contacts on Map Sensor (again)

car much the same but slightly better.

idle still sticks at 1800 revs unless it is brought down with gears or through blipping the throttle. Idle feels slightly smoother.

I think that on looking at the plugs it was running a bit rich as there was also a fuel smell.

My conclusion is that the inlet manifold gasket is leaking and this is sending funny signals to the MAP sensor to the ecu.

Other options are:

throttle body stuffed (was last changed at 30,000 but now has 80,000 on clock)

Wiring connector to Map sensor needs replaced (can this be done without a new loom?)

I will be changing the inlet manifold gasket next and will report back. Any other thoughts appreciated as it is doing my head in!!

Can't we all just go back to carbs?