280z gas tank cap question

[antsorce]

just bought a 1977 280z 5 spd over memorial weekend. the car has 80,000 miles and is very clean (amazingly clean for a car from milwaukee.) appears to be all original just needs a little tlc. The car sat for a while and runs a little rough, hard to start cold but runs well cold. once car comes up to normal operating temp the car seems to hesitate a bit especialy starting out in first from a stop and while shifting between gears. runs great on the freeway or when i excellerate hard.

items replaced so far include vac hoses, fuel filter, egr, cap and rotor (Plugs and wires appeared to be new)

a few things i am unsure of, first while cleaning the interior I noticed a wire linked to the radio fuse on the fuse box in the passenger seating area. followed the wire behind the seat and discovered that it is powering the fuel pump could this be contributing to the problem?

second when i remove the gas cap there seems to be alot of pressure built up is the cap supposed to be vented?

been reading alot about rust in the tank and clogged pic ups just wondering if anyone had any ideas before i go ahed and drop the tank.

p.s. stoked to be a new z owner love the car been looking for on for a while finaly found a clean one

[sblake01]

The pressure is supposed to be there when you remove the gas cap. Part of the evaporative emission control system which they are closely scrutinizing now on the California smog checks. Hard to start when cold could be a problem with your cold start valve/thermotime switch circuit or lack of fuel pressure. How does it start when it's warm? The hesitation could be due to a bad water temperature sensor or a bad connection at the sensor. I say 'could be' because these item have been known to cause those problems but you need to run through the troubleshooting procedures to be sure.