I got a full magnex exhaust system fitted to my MK1 172 last week but have a problem with it. when i start the car in the morning after about 20 - 30 secs the revs drop away and the car just about stalls. This will last for about 10 secs then the revs pick up and the car is fine. However yesterday i was out for a drive and i am driving along just the thing, start pulling away from a roundabout, reach 40ish and the revs sart to drop. No matter how hard i pressed on the accelerator the car would not respond. This only lasted for a few secs but it is pretty worrying.
I took it back to the garage who fitted the exhaust but he was sure it wasnt related to the exhaust. But that is the only thing that has been changed recently. I was thnking he may have damage the Lamda sensor. I am taking it to another garage this week and will see what they say.
How much would a new sensor cost ? Do you think it may be a job for the renault dealers....