I have an 04 envoy 4.2. Lately she's been hard to start. Turn the key she just cranks. Try again she'll start. Swapped the fuel pump relay. No change. Tested fuel pressure at the port near the filter. Key on engine off about 20 psi and drops. Key in engine running 45 psi. Changed the filter and no change. Also p0171 lean bank #1 code. And another thing once the key is turned off from running pressure immediately drops to zero. No external leaks or smell of fuel. My gut says failing fuel pump due to the low pressure knowing spec is line 57 psi. But I've read a lot about the regulator being the cause. Wanted to know your opinion. Thanks in advance.
04 envoy hard start woes.
- Thread starter irishlefty333
- Start date
Mooseman
Moderator
If you smell gas and isn't holding pressure, my money is on the pressure regulator. Pull the hose of it and check for gas there. Or there's a leak in the pressure line somewhere.
Mooseman
Moderator
Re-read your post and you said no smell so forget what I mostly said. If your pump is original or has been there a long time, I'd go ahead and change it. You could try the regulator first but they have been a low failure rate part on this platform but not unheard of.
No smell and no external leaks
thanks. Fuel pump is ordered. I'll let you you know how it goes.