99` Tahoe and the infamous CEL

[kennythewelder]

Yea that will do it.

Appreciate the advice, turned out to be the rotor and cap on the distributer. Wasnt delivering spark under load

 

[Oldblue98]

Have you checked your fuel pressure ? Vortecs are very sensitive to fuel pressure. The fuel pump gets week in time, and doesn't deliver enough fuel pressure at WOT. It took me forever to figure mine out, the first time mine did it to me. Vortecs need over 60 PSI pre start, and in the 50s once they are started. You would think, that if the fuel pump is bad, that the truck would not run, but that is not the case. Here is the video I used to diagnose mine when it was failing. It is worth doing a fuel pressure test, to eliminate if you have a bad pump , or not. Also when mine was going out, I was getting some other codes too. I was so frustrated before I figured mine out that I was thinking about selling my truck. If it is your FP, then you only want to use an AC Delco, or a Delphi pump. Don't use anything else. I tried that too at one point. The other brands, dont put out the pressure that you need. I have had my truck sence 2002. I think I am on my 4th or 5th pump. If you don't have a fuel pump tester, you can rent one @ Auto Zone

I just know I am going to regret saying this.. But since 1998 Blue is on fuel pump #2 and I replaced the original with a Bosch pump which at the time everyone was saying Bosch was the way to go !? All I can say is the Bosch is 7 years old now. I figure now that I have said that it will be time for fuel pump # 3 lol .
It is kind of like bragging on getting no tickets and you drive around the block and get a doozy.

 

[kennythewelder]

I just know I am going to regret saying this.. But since 1998 Blue is on fuel pump #2 and I replaced the original with a Bosch pump which at the time everyone was saying Bosch was the way to go !? All I can say is the Bosch is 7 years old now. I figure now that I have said that it will be time for fuel pump # 3 lol .
It is kind of like bragging on getting no tickets and you drive around the block and get a doozy.

If it is working for you, thats good. To me, its just not worth taking a chance on a maybe. I know a Delphi, or AC Delco will be rite. I can't tell you how long my current Delphi pump has been in the tank, but it has been several years. At one point, I put a cheeper pump in, and had to change it in less that 1 year. Just passing on my experiences.

 

[Oldblue98]

If it is working for you, thats good. To me, its just not worth taking a chance on a maybe. I know a Delphi, or AC Delco will be rite. I can't tell you how long my current Delphi pump has been in the tank, but it has been several years. At one point, I put a cheeper pump in, and had to change it in less that 1 year. Just passing on my experiences.

As I always do I over think things and was looking at reviews and decided on the Bosch and at that time it was not because it was cheap, because if memory serves me correct it was close to 300 smackers for the pump. And today if I was to change it out I would go back to Delphi or ac delco. I know you can wear yourself out with economy pumps changing them, Such as airtex etc. I know it is not fun to do, because on my truck it is easier to pull bed than try to fumble with the tank.

 

[kennythewelder]

I guess I'm lucky, IDK, but on my 97, I can change just the pump. I don't have to change the complete unit. I know my wife's niece has a 97 Burb, and they have to buy the complete unit. They can't just change just the fuel pump like I can. IDK why GM did that.

 

[jsfrmsj]

I would definitely replace the 02s first. I remember reading somewhere that a bad coolant temp sensor would cause misfire issues and would force the truck into OL all the time.