Welcome to JustAnswer.com! My name is DriveFast71(Ron) and I will do my best to answer all of your questions completely and accurately.
The EGR Valve is located under the Intake Manifold.
IF you are looking at 4 mounting screws, you're on the wrong part. The EGR is help in by 2 mounting bolts and has 1 electrical connector (if you click "view full image" on the above images, you'll get a pop-up window with a close-up view).
I don't understand the question: "is the throttle position sensor connected?"
The TPS is located on the throttle body.
You were "told it was bad"? Do you have "p-codes" that pointed you to this being bad?
My apologies if I communicated poorly.
1. EGR: From diagram you sent is it the part with the red arrow pointing to the circled part labelled "1". Is it simply on top of intake manifold? There is a part there numbered 72f2...eit265. If not on top of manifold, does it face the firewall?
2.. Yes check was run using eauipment that connected to tracker and displayed p codes, for throttle sensor it was p0121. Person who did it said it was RELATED (I said connected, sorry) to EGR valve going bad.
Correct. #1 in the top image, and labeled in the 2nd as EGR Valve.
Ok. When you retrieve a p-code, this is your "starting point" for the diagnostic procedure. The P0121 is a fairly straight forward code pointing to a problem in the Throttle Position Sensor. Check the wiring harnes to the sensor for any loose or broken wires. Check the throttle plate (butterfly plate) for any signs of "sticking" or "binding" (even giving it a good cleaning with some carb cleaner may help!). If the visual inspection checks ok, and/or the plate cleaning does not solve the problem, suspect a faulty TPS and replacement should solve the problem.
As for your question- in this case, no the TPS and EGR are not related. I would concentrate your efforts on the TPS when you have the P0121.
I suspect you may think you're dealing with a complete idiot and I'm beating a dead horse by not being clear. There were 2 p-codes, one for EGR and one for TPS.
What I'm trying to clear up is this: Is the EGR valve located on top of manifold or on side of manifold facing firewall?
Oh! I didn't know there were 2 codes. I thought just the P0121.
What was the other code? (Let me double check it for you, to see if there are any Service Bulletins on it, or "known issues")
The EGR is on the side of the intake, just to the right, and a little lower than the Oil Dipstick.
Did not write down code for EGR but chevy dealer and autozone both had same code for EGR.
I am REALLY sorry, but please help a 54 yr old senile guy understand location. Is the EGR attached to:
A. Firewall side of manifold
B. Passenger side of manifold
C. Driver side of manifold
D. Radiator side of manifold.
Going nuts cuz nothing looks like pictures of what you sent. If you can give me a b c or d, I'll take it from there.
Passenger's side of the manifold. Here's another view (keep in mind, more parts removed for clarity).
OK, THINK I got it, please confirm:
TWO (correct?) bolts that hold egr valve in place, from diagram the "head" of the bolt (where I attach wrench) when installed faces firewall, "bottom" of bolt points to radiator.
If correct, believe I've got it.