Hello all - I bought a 1970 E-Type this week and I an just getting started working through some issues, but first thing is first....pictures:



The car has 71k original miles, purchased from the original owner's son.

The issue I am investigating is a miss at idle - worse when cold, better warm, but never completely clears. I actually drove home with the choke out slightly to keep the revs a little higher - seems to take a very long time to get warm, though as I said, the miss never clears completely. I checked spark and all wires are receiving good, strong steady spark, so I moved onto vacuum and encountered and odd thing that may be normal for these cars, or maybe not, so I thought I'd check:

1) I tested vacuum coming from the front carburetor, the line that typically goes to the vacuum can on the distributor (vacuum retard on these cars, if I recall) . I only got 2 - 3 HG vacuum however - seemed really low to me. Revving the engine did not change it, may even have gone lower (which I'd expect when you open the throttle) but there was no higher reading on overrun. What should the vacuum reading be off the carburetor? and is it ported or manifold vacuum? As this is emissions, I suspect ported.

2) There is a metal line that runs along the driver's side cam cover, connects to the head at the front - (Crankcase ventilation / precursor to PCV valve I suspect). This line then follows the driver's side cam cover and eventually connects to a canister behind the battery, adjacent to the brake vacuum booster. I imagine this is akin to a charcoal canister or other emissions-related gas recovery system - this line had no vacuum at all. The same connector at the front of the engine also has a tube leading to the carburetors - shouldn't this have some vacuum, one direction or the other? The line is broken before it gets to the canister beside the brake booster, no vacuum signal at all. I expected there to be a vacuum signal to draw / ventilate the crankcase and draw the fumes back into the carb to get "reprocessed".

Even though I am somewhat familiar with the 3.8 from the MK2, this emissions-clad 4.2 is new territory. I've also ordered a few books.

Thanks,

Allan.