(T) What Could this Be!!!!!!!!!!

i have an "52" 1.6 16v 3 door stilo, recently ive been experiencing idle problems and unsteady tick over( can hear from the exhaust slightly up and down rumble noise) 1 month ago i had the cam belt changed along with the air con belt and Alternator belt. since then i have 2 failed coils and replaced them. since saturday i have had the unsteady tick over and i have now notice little dead spots between 1000-3000 rpm in 1st and 2nd gear.

ive used the guide to clean the thottle to get rid of the black stuff

i also can smell fumes when putting the heaters on in standing traffic since the unsteady idle

any 1 got any solutions no fault codes are appearing on my obd2 scanner

Who did the cam belt change ..if its one notch out you will get the trouble you are experiencing ..also as you have a 52 plate car it might be worthwhile checking if you have had all relevant software upgrades for the car ..IE throttle body and ecu ones ..

Fiat did the cam belt change, but they changed it about 4weeks ago now , would this happen after that long?

It would be instantly recognisable after the cam belt change if it was misaligned

You haven't mentioned your mileage or the state of the plugs. Some people have been known to change coils when it's actually the plugs

As you can imagine, everything has to be dead right for a good steady tickover. Fuel/air mixture, plugs, lambda sensor, free moving throttle valve
Lambda sensors can often get sluggish but still remain within spec without firing up any warnings.

So
Plugs
Air filter
Make sure there's no gunge still left around throttle valve
Reset ECU

Get a lambda readout at tickover

cars just done 48000 and has an oil change and oil fitler every 10 000 miles
sparks are a greyish colour which if i remember is a good sign there about 20 0000 miles old ive replace the 2 coils and that sorted out the coil problem but this feels different compared to the broken coil symiptons!

is the update free?

so can we rule out the cam belt as that was change about 4 weeks ago!

sparks are a greyish colour which if i remember is a good sign
Better than black or oily but it's the gap that's important,especially if they're single pole plugs as they wear down faster

there about 20 0000 miles old
that's getting on a bit

ive replace the 2 coils and that sorted out the coil problem but this feels different compared to the broken coil symiptons!
Yes coils are pretty dramatic


is the update free?
No.

So can we rule out the cam belt as that was change about 4 weeks ago!
Most likely unless you've only just noticed it's misbehaving or it's slipped a cog which is very rare unless the belt tension was set badly

I'd go with a new set of plugs, nothing special, about £12 for all 4 from sparkplugs.co.uk then see if you can check out your pre cat lambda

Agree with the rest of the comments, but also could be a manifold air pressure sensor faulty, if you need one I have one for sale on ebay. An easy way to test your lambda sensor is to rev engine at 2500 rpm and listen for the engine speed to increase/decrease, if a lambda sensor is slow in operation the engine will pulse and this can sometimes be felt when driving.

well ive changed the spark plugs and replace a 3rd coil (spare i keep with me) so thats 3 replaced and 1 left i imange that will go sometime soon, its stoped the tick over a unsteaded tick over and ive erased the engine management light with my obd2 so everythink is fine for now, but what is the gap size for the spark plugs? everytime ive changed them ive never ajusted the gap!! maybe i should this time what are the effects? they were all grey/brown apart from one which was black what does that mean?

Maybe a vacuum leak? check that someone hasn't disturbed/ forgotten to put back on a pipe on the vacuum circuit.

vaccum circuit wear would i find that

Black, sooty plug = rich or not firing consistently. I wouldn't mess about, I'd just renew the plugs. At 20k they're getting on so it's a waste of time just putting the old ones back in. Gap is best at 0.9mm

For starters, have you recharged your battery?

OEM plugs are at 0.8, but it seems to idle better at 0.9. Less diesel sound at startup aswell. I can recommend Denso plugs for the 1.6 litre.

Morten.

cheers i need to gap them today then !!! im also going to clean the butterfly thottle body thingy!