I have a Fiat Marea Weekender 1.6. I have had problems with low power and had the CAT re-engineered. I still have the problem and yellow engine light has returned. There is a smell of exhaust fumes at the back of the engine and i suspect a cracked manifold. Would this cause low power and is it relativley easy to change the manifold? As soon as the revs pick up the car flys with speeds well over the speed limit possible. All the plugs are good. Garages just say they need to hook up a computer and read whats wrong. Help

Hi,
If you have a hole in the inlet manifold or gasket then you will have low power at low revs and run hot at high revs.

A small hole in the exhaust manifold shouldn't cause any problems unless it was big enough to reduce the gas flow past the lambda sensor.

A diagnostic check at a garage is easier. Try to negotiate a free test if you have the fault fixed at the garage.

Thanks, i'll get it to the garage assoon as I can. I have taken off the aluminium cowling over the exhaust manifold and found a crack on the cast iron manifold that goes from the engine side to the bolt for the cowling at the furthest point. I have no feeler gauges but have been able to insert a piece of thin paper in the crack to a depth of about 2mm. I guess this might be enought to affect the lambda. I did ask about this the last time i was at a garage and was told no errors were showing on it. I guess the lambda component is fine but not getting the airflow so affecting performance. i'll keep you posted when i get to the garage.

Replaced the section of exhaust with a meshed flexible section, this lasted two weeks and engine light on again. About to have throttle potentiometer checked and replaced if required as part of a deal to trade in for a Stilo Multiwagon. Suspect it still might have a fault after this so it has to go. If I dont like the multiwagon I'll look for a Marea W with one carefull lady owner and low milage maybe with the jtd engine.