1 like 0 dislike
336 views
by

I have a 2001 GMC Yukon 5.3L. It has both codes P0174 and P0171. The only problem is a very hard start every time. And also lack of throttle response and power. I cleaned the EGR valve and TBI and also ran additives through the gas tank. Also does have a clean KN air filter in it. Thanks for ur time, Stephen.

Vehicle: 2001 GMC Yukon 5.3L

1 Answer

0 like 0 dislike
by

what octane fuel are you using? low octane fuel could cause this problem, fill up 91 octane from Shell using a good fuel system cleaner like BG 44k or Chevron with techron fuel system cleaner, and maybe do an intake flush also.

You may check for an intake leak, you can spray brake cleaner around the intake manifold and intake tubing and see/hear if there is an RPM change. Don't spray brake cleaner on hoses and wires, just hard material.

here is a youtube video showing 

other than if that does not fix the issue oxygen sensors will have to be checked, and fuel pressure which is supposed to be 55-62 psi with the key on and the engine not running. You may also consider doing a tune like replacing spark plugs and etc.


 

Related questions

1 like 0 dislike
1 answer 1.0k views
1 like 0 dislike
2 answers 253 views
1 like 0 dislike
1 answer 276 views
1 like 0 dislike
1 answer 409 views
1 like 0 dislike
2 answers 379 views

36.2k questions

32.2k answers

1.3k comments

22.8k users

Need A Repair Shop?
Find local automotive repair shops in your area.
Does your car have Safety Recalls? → Check here
...