Ensure you order an AC Delco, and not off Amazon or EBay, I’ve received counterfeit junk from both! I got the real deal from RockAuto

 

OK For what it's worth... replaced both the evap canister solenoid and the purge solenoid and neither item changed the situation.
I am going to live with the odd startup behavior until 1) I don't need this automobile 2) it or I die. Whichever happens first.

 

Thought I would update this post on the weird start-up behavior.
I recall that when I first purchased this used vehicle it was in the winter with cool weather and I did not notice the strange behavior until warmer weather of spring. Well, now that it's winter again I note that on initial start-up the car behaves nicely and starts right up and goes to idle with none of the previously mentioned behavior. Even though I have not been using the car regularly I have confirmed this on a number of occasions in recent days. But to add to the mystery I noticed today that if I shut the engine off soon after its perfect start-up and the start-up again....it does the same darn thing it does in the warmer weather. Starts with rough idle and then revs up and settled down to normal. So I am hoping this noted change in behavior might give some expert here an idea of what might be happening and could share that idea with me. :) I read somewhere recently that a faulty brake booster vacuum line chaeck valve could cause isses similar to what I am experiencing. Is that possible and is there such a valve on this engine and if so where is it?

 

If that’s a possibility, then so should the MAP sensor, first off check the plastic pipe that runs from the under hood EVAP valve to the intake manifold near the MAP sensor any nicks in the o ring? Is the fitting connected tightly, possibly spread a little silicone grease on it to ensure a good seal and while your there same for the MAF sensor lube the o ring to ensure a hood seal.

Same for the brake booster hose , it connects to the intake manifold at point #2 , marked by a red arrow
The check valve is #5 also look for the red arrow



For the price order a new check valve


Don’t forget the discount code!!

 

Sounds to me like the computer does not know when to choke on start. Is the ambient temp sensor working?

 

donbrew : I don't know the answer to that but it makes real good sense to me. Can you tell me how to check and where to find that sensor?
Oldblue: Thanks for the details. I will do as you suggest regarding the O-rings and a new check valve looks like a very small investment! :)

 

The ambient temp display on the dashboard.

 

Will check that but where would the sensor be?

 

Under the front bumper, see post #2

https://www.chevyhhr.net/forums/hhr-...p-gauge-17158/

 

Ok now this is starting to make sense. This vehicle is a salvage vehicle and i have had the bumper off to install a tow system for behind my RV and I never saw a temp sensor. So now that tells me I need to locate where it was re-located to. Can you tell me where it would be connected that I can then trace to where it is? :)