People on here are going to need way more information if they’re going be able to really provide you valuable advice.
What’s the history of the car? Has it been sitting or is this something that just started? My first place to start looking is fuel on these cars is the fuel system, old fuel, rusted tanks clogged filters on old cars is a common problem and very common on Zs. Let’s make sure you have clean, unobstructed fuel at the right pressure getting to the injectors.
1. If the gas is old, get ride of it. (280z have a fuel drain plug on the bottom of the tanks). If it come out rusty, smells weird or has any sediment then have bad fuel and also a clogged filter. Don’t try and start the car again intel we fix this you don’t want to clog the fuel pump or the injectors anymore with debris
2. If fuel is new and clear, then change the filter in the engine compartment (passenger side near radiator area).
Get those items completed and them report back your findings. Then we’ll proceed from there.
Yes sorry about that. Well I bought a bmw 328 that has a L28e motor in. The previous owner said that the car was running fine till he filled up on fuel then the car started giving the problems. The fuel that was in the petrol tank looked clean and rust free.
id check for vacuum leaks. get a small handpump from harbor freight and plug the "out" side into the brake booster inlet on the inake manifold and the "in" side of the pump put a lit cigarette and pump. The smoke will exit where the leaks are.