Car starts in the morning fine, won't start without gas pedal later on in the day

So we got a salvage title Chevy Equinox 2006 a month ago. Cheap, only 50 000 miles on it and needed an extra car. The dealership said that the muffler was damaged in an accident. Whoever bought it from the auction welded it, the car ran and the dealership bought it, put the rear bumper back on and that’s it. No idea of what the accident was like, since the car has all the original body parts, no dents or scratches. So guesssing whoever owned the car before us backed up onto something. Anyway, 2 days in I notice a pattern that the car starts fine in the morning. And then if I start it in an hour up to 6 hours it won’t start without me adding gas pedal. It kind of chuckles and then just doesn’t start. I’m sure you can tell I’m not car smart, so I’m looking for ideas if this is something that will cost thousands or just hundreds :slight_smile: thanks!

There are a whole bunch of things that can cause that but one of them is the MAP sensor. I just did an intake gasket on an 04 Grand Prix with the 3800. I don’t know what motor’s in yours but the location of this one made it so that it was obvious to me that it was cracked. It separated a little and, of course broke in two when I attempted to remove it to soak the upper intake. It used to only start if you gave it throttle while cranking, now it starts when you touch the key, no throttle necessary.

Good luck, if there’s anything else I can help you with, feel free to ask.


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It won’t have any dents or scratches because it was probably repaired and repainted. Most salvage cars LOOK great on the surface. But it was declared a total loss at one point and that is not due to a bumper and muffler being damaged. If you know what you’re looking for, you may see evidence of the extent of the damage. Most of the time, they spray an undercoating like paint onto the frame or unibody underside to mask all the welding/repairs so it looks brand new. How do you know it’s all original body panels?

I must have looked at a half dozen salvaged trucks when I was searching for a replacement for my trailblazer. They all had super low miles and looked mint on the surface…

The starting issue may be something as simple as needing a throttle body cleaning but it will take someone with mechanical skills and the vehicle in front of them to diagnose it properly.

Just a stab in the dark, I wonder if the wreck (and if it was totaled, it was a lot more than the driver backing into a curb) messed up the fuel tank’s venting. Perhaps it’s blocked/pinched off somewhere, and that makes it vent very slowly, so it’s not hard-starting because the engine is warm but because the fuel pump was running too recently.

Let it sit overnight and the tank has time to vent.

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should be the 3.4 v6. maybe the temp sensor is bad. how do you apply throttle as you crank? hold it 1/4 open? 3/4? i had a 3.1 v6 that started fine cold but would always start/die when hot. if i blipped throttle after it started it would idle fine. it was the 2-3 sec after it started. turns out the throttle bore had carbon buildup. cleaned that and it started smooth

Another idea, it’s running too rich. Not a problem when the engine is cold, but warm, you have to step on the gas pedal to allow more air into the engine, which leans it out a bit, before it will start. Leaking injector or problem with the evap system purge valve maybe. Check the diagnostic trouble codes, and ask a shop to measure the fuel trims.

holding throttle open when cranking will disable injectors to clear flooded motor. yes i did read that online once. was it a carryover from carb days theory? dont know if 09 vintage cars still use that same tech