kld280zx

Hey guys,

I'm loving this forum, been learning a lot reading here

I've got a 79 280zx I'm working on....

It fires right up when it's cold, and runs and drives great. Once it starts to warm up, it will still run and drive, but:

1) Revs drop slooowly when I let off the gas
2) There's a bit of hesitation when it revs up, especially if I punch the gas pretty quickly. If I slowly go on the throttle, it's smooth

Now when I got the car, it was running really rich, getting crappy mileage, and I could see the air flow meter had been cracked open.

What I've done so far:

1) New plugs, plug wires
2) Cleaned all electrical contacts
3) Recalibrated AFM according to a procedure on another club's website
4) Tested water temp. sensor, thermotime switch (both ok)
5) Visually inspected air regulator to make sure the valve inside was not stuck
6) Timing
7) Visually inspected vacuum lines

I've heard a bad EGR valve can cause this kind of problem, so that's next on my list, along with a more thorough check of the vacuum system

One strange thing I found.. the vacuum diagram shows there being two vacuum delay valves in the system. My car has the one right in line with the EGR, but not the one in line with the vacuum canister. So I'll have to look into that too.

Last issue, this is the most worrisome question: there's some brownish crap that was on the thermotime switch and water temp sensor, and I was concerned that this was a result of oil in the coolant, aka busted head gasket or warped head. However when I was draining out some coolant (about 2 Liters) it was a normal color. Should I be concerned about the brown stuff?

Sorry about the uber-long post, I'm new to the whole online forum thing!