[68 TT]

On the 4.3 SPFI engines with the similar spider injector system and plastic poppet valves they put the fuel pressure regulator inside the intake plenum. They are known to leak fuel when they go bad and it will cause fuel economy and tuning problems. I had to replace mine on my 95. Originally thought it was the spider injector assembly that was the problem but that turned out to be good. Replaced the regulator alone after seeing it was obviously leaking along with the in the plenum fuel hoses and it was running better than ever.

I don't know if the V-8 version has the same in the plenum fuel pressure regulator setup as the 4.3 SPFI engine but I thought it was worth mentioning as something to look for in case it does.