Another question about the 156.

[robsco]

Right, so the thermostat is done.

Now, there are a couple of flat spots at specific rev ranges which are quite pronounced. They are at 2500 and 2800rpm. When the engine is cold, she judders to such an extent that between 2 and 3k the car refuses to accelerate. To pick up pace again, I have to take my foot off the accelerator and then try again until it manages to pick itself up. Once warm, it narrows down to the aforementioned revs, but is still noticeable.

I thought about the MAF, but would that have an effect only at these revs?

Thanks.

[14-7]

robsco said:

I thought about the MAF, but would that have an effect only at these revs?

Unplugging the MAF to see if the problem disappears is the easiest thing to do. It will idle poorly but should drive alright.

[RicksAlfas]

Might be worth changing the water temp sender.
They're not expensive and do fail.

[Red Firecracker]

Well worth doing the ECU reset, as described here;

Alfaowner.com ECU rest Thread

[robsco]

Right, I'll give the ECU reset a whirl first to see if that alleviates it. How do I unplug the MAF should I need to, 14-7? If that turns out not be the fault, I'll get a temp sender on order.

Thanks for the suggestions, I knew I could rely on the Alfa forum reprobates!

[14-7]

robsco said:

How do I unplug the MAF should I need to, 14-7?

Which engine? If it's a petrol then from recollection the MAF is located just above the air intake (normally bottom right of the engine bay behind the headlight/foglight).

There is an electrical connection just above the air filter box with 2 torx screws holding in the MAF. Just unplug it. You will probably get an error message on the dash but that's just the ECU working properly.

[robsco]

Sorry, its the 2.5 V6. I'll give it a go as soon as the weather improves, she's currently buried underneath what looks like a decade's worth of snowfall.

[waynedear]

When you dig it out i would do the MAF unplug first...