Running Rich and Squeaky U-Joint...

[usamarshal]

Hello everyone, just want to say I really enjoy this website and have gathered a lot of good information when working on my Tahoe. I have a 2000 Z71 5.7 Liter with old body style and having trouble with my vehicle running rich. I get the 172 and 175 codes after I replaced the fuel pump and fuel filter just recently. I replaced all four oxygen sensors along with changing out the plugs, plug wires, and rotar and cap. I have a new air filter and replaced that thermostate and thermostate sensor which helped my engine run at its optimal heat range. I also notice that when I'm driving and come to a stop that the RPM's go down and then back up, like its about to stall out. I'm thinking it may be a fuel injectors, but I didn't get any codes for that and the scanner didn't pick up anything wrong with them when doing the diagnostic. Any ideas of what I may be missing?
I also would like to know if my vehicle has any grease fitting for the u-joints. Would I bet looking inside the u-joint itself and would the fitting be a zerk fitting? I noticed that there was no movement of the u-joint when I pushed up on the driveshaft and both the front and rear joints are solid. Any help with that would be greatly appreciated too.
Thanks everyone and I hope to hear from anyone soon, Skip

[horse482]

The rich problem is probably the fuel pressure regulator. You have to pull the top of the intake to get to it. The factory u-joints do not have grease zerts.

[usamarshal]

I was thinking it may be the fuel pressure regulator last night so I hooked up my fuel pressure gauge and turned on the engine. It was reading between 60-70 psi and when I turned it off it went back to 54 psi and held steady without going down in psi, even after 5 minutes. Not sure if the fuel pressure regulator would be the problem.
As far as the u-joints go do I need to grease the inside of the joints since there from the factory or do I have to replace them? Thanks again for the help, Skip

Originally Posted by horse482

The rich problem is probably the fuel pressure regulator. You have to pull the top of the intake to get to it. The factory u-joints do not have grease zerts.

[horse482]

Once you take the u-joint apart you will want to replace it. It's not worth your time to try to put grease in the old joints. If they are squeeking then they are already dry. What is the fuel preasure at when the vechile is running?

[usamarshal]

Ok, I'll do that then. Hopefully it won't be to much of a pain to do it. The fuel pressure holds steady at 70 psi for the most part. Once the engine is turned off it goes back to 52-54 psi. Thanks again for the help, Skip

Originally Posted by horse482

Once you take the u-joint apart you will want to replace it. It's not worth your time to try to put grease in the old joints. If they are squeeking then they are already dry. What is the fuel preasure at when the vechile is running?

[usamarshal]

Well, I found out what the problem is. A buddy that works for a Chevy dealership said he'd look at it today. The problem was a small leak in the FPR and Lower Intake Gasket. Both are fairly easy fixes and will cost me under $80 to repair. He gave me a quote of what the dealership would charge me if they did it. The cost was over $900. I think thats where the car industry gets their money...lol...not from the sales of the vehicles...shesh...He also stated that the u-joints were dry and thats why they squeak...It makes me wonder why GM would install u-joints that can't be lubricated or greased. Anyway I'll keep everyone up to date, Skip

[Blk982drTahoe]

I just replaced my U-Joints this past weekend. Not a big job and they are not expensive. You can also get some that have zerk fittings. Hope this helps.