Why is my 2 door Tahoe such a slug? Video inside.

[LA SILVERBIRCH]

I have ran out of ideas of what is causing my stock 1999 2 door Tahoe 4wd to run so sluggish. I have already done the following and nothing has helped.

*deleted catalytic converters
*new ac delco plugs and wires
*new ac delco rotor and distributor cap
*sea foam thru the vacuum hose
*cleaned up the throttle body intake
*new fuel filter
I am getting code P0430.

Please see videos below.
All runs where done at WOT.
http://www.youtube.com/watch?v=qxhuMA8_s-Q
http://www.youtube.com/watch?v=ijXjE4SjYQA

 

[Gzes]

Nitrous

 

[2000tahoeZ71]

The 0430 code is a catalyst insufficiency code due to well, not having cats. Have you checked fuel pressure?

 

[LA SILVERBIRCH]

Nitrous

I dont think that would be a good idea on this 140,000 engine.

---------- Post added at 12:29 PM ---------- Previous post was at 12:25 PM ----------

The 0430 code is a catalyst insufficiency code due to well, not having cats. Have you checked fuel pressure?

havent checked pressure yet will be doing so this weekend it seems to me that it falls on its face after 3500 rpm and stuggles to get to 5000 rpm.

 

[SunlitComet]

Well taking the cats out was a bad idea. Doing that effectively changes the flow of gases and can make the engine act like the cam profile has changed. I have seen a few vehicles that lost top end power because they thought it was restrictive to the power and cut them off. Also you don't want to put Sea-foam down a vacuum line in a vortec. There is a proper way to do it. Check your fuel pressure becuase you may have a lack of it at higher rpm or you have some serious torque management going on at higher rpm. If you are leaning out at high then pcm will cut back the timing if it see's detonation as a result. Ensure your air filter is clean.

 

[2000tahoeZ71]

My truck was kinda doing the same thing after I replaced the lower intake gaskets. Had strong midrange power but fell down when it wound up. Took it a while to throw a code, but came down to I hadn't plugged the MAP sensor back in. My brothers 96 kinda stumbles when you put her to the mat, and takes a while to start. We are 99% on the fuel pump.

 

[Gzes]

I was playing lol but I am gonna run a zex wet kit on my prelude with 180k although it is gonna have lots of new goodies

 

[LA SILVERBIRCH]

thanks for all the suggestions great info on this forum... i will check my fuel pressure this weekend can someone please advise me on what the pressure should be.

 

[2000tahoeZ71]

If I remember correctly around 55-60 psi.

 

[SunlitComet]

Use this diagnostic sheet to test the whole system. but report the numbers back here before you go buying stuff.

http://www.sunlitcomet.com/pdf/auto...96-chevy-tahoe-fuel-pump-pressure-testing.pdf