Rough Engine Idle can't figure it out!

Hello Everyone,

I'm new to the forum so nice to meet those of you out there. So lets get on to my detailed question. I have a 2000 Escalade with the 5.7 ltr. I have recently replaced the fuel pump about 3k miles ago. I have noticed afterwards about 3 weeks or so that the truck idles rough or misses about every couple of seconds. Not a bad idle though, just something I can tell through the seat of my pants. It runs fine through the rpm band and still gets up and goes. Just when I come to a stop and let it idle does it idle off a bit down to 650 and goes up occasionally to 750. The check engine light has accompanied the rough idle with a emissions leak, but when I put the new fuel pump in the tank I did it by the book and made darn sure the tank to pump gasket and retaining ring where on perfect. All hoses went back together and the new fuel pump wiring via the instructions went together easily and on the right way. I've done the pumps before so I believe it was correct to my knowledge. But with that idling issue it could be a number of things. Personally I think it's the EGR vavle recirculating incorrectly. But i took it off and clean it up and it's not siezed. So my dead end has lead me to thinking it's maybe a fuel pressure regulator or throttle positioning sensor. I have tools, but nothing really to check the fuel pressure and usually it's just cheaper to replace the TPS instead of fighting with it. Do you guys think I'm on the right path or did i miss something somewhere? Any help would be greatly appreciated!
-Blaine

Make sure you reconnected the purge control solenoid hose that goes on the inner side of the gas tank that will cause a vacuum leak when the purge solenoid is energized along with a emissions evaporative system leak

Ok I'll try that. That's the hose towards the driver (front of the vehicle) on the tank correct?

So I checked the purge valve. I traced it back up to the intake plenum and it seems like the lines and purge valve check out. The lines to the gas tank appear to be connected in all the right places but it makes me want to drop the tank and integrity test the connections... The purge valve looks good seeing that the engine bay stays clean enough to eat off of.( makes believe all the hoses are good and strong and ring gaskets lively still) but! I do have a mighty vacc. Do you think I can disconnect lines and pressure test them?

Yea sorry about that didn't mean to leave you hanging.. do you know if it has the new updated CPI fuel injector assy

Personnaly i haven't taken off the plenum so i doubt it but i'll get to that this weekend and get back to you on it.

Ok. The way you can tell is take the air intake duct off the throttle body and with a flash light and small mirror lok to see if the injectors have electrical connectors on them those would be the new updated ones, the older style just have thin tubed lines no connectors

Yeah it has the old crummy spider injector assembly. Looks like I'm saving up for the new updated injector system. I attached a picture but I don't think it'll upload.

Oooop never mind!

Yeup definitely the old style