New 99 Tahoe owner--what mods first for easy power/mpg?

[Goldhawg]

Any comments re the throttle body?

BTW, I got the truck off the shipping truck. First stop was direct to Ziebart to help keep it CA rust free in salty Ohio--or at least slow so I can enjoy for several years. This is why I was willing to pay the shipping cost to get one from CA--see pics

EDIT: forget comments on the throttle body; just bought one of the ported ones already done off ebay
http://www.ebay.com/itm/370322497749?item=370322497749&viewitem=&vxp=mtr

Couldn't get CFM-tech to either answer their phone or emails, maybe they are not even in business anymore? In any case the ebay unit was considerably cheaper and had good feedback from buyers

 

[rolfsent]

Any comments re the throttle body?

BTW, I got the truck off the shipping truck. First stop was direct to Ziebart to help keep it CA rust free in salty Ohio--or at least slow so I can enjoy for several years. This is why I was willing to pay the shipping cost to get one from CA--see pics

Hey! We're not that salty!!! At least in Cincinnati lol

 

[96redsport]

Let me know how much of a difference that ported TBI makes... Something I may add to my upgrade list!!

 

[Goldhawg]

I looked at the records that came w/the vehicle, and it shows the PO replaced (w/in last 20k miles): lower intake manifold gasket, and both valve cover gaskets, the fuel pump and FPR, serpentine belt, and tranny fluid/filter.

Conspicuously missing is any mention of spider. Nor do I even see tune up issues (cap/rotor/plugs/wires) and it is a bit hard to start (turns over for a while) but throws no codes. I will check the cap and rotor today and if any issues replace all (including wires and plugs--sticking w/stock AC-Delco plugs).

Question, if its not throwing any codes should I preemptively swap out the spider, or is this something that I can wait on till I know I have a problem? Really, I guess another way to ask, given I have 120k miles, am I already on borrowed time or do these sometimes make it much longer such that it might make sense to wait? Seems like everybody on here that swaps wished they'd done it earlier, but that may just the people that had problems.

Also, I don't see any O2 sensors replaced; I'm thinking it might make sense to just do this for maintenance--but again I have no codes.

Thoughts?

 

[SunlitComet]

at only 120, i might wait a bit until you see problems. unless you are needing to stress over it. as for the O2's have the waveforms analyzed for proper wave forms. it will clue you in on how well yours cats are doing too. i will eventually get some tests done to determine a good replacement point based on age and mileage in a certain maintenance kept vehicle but i cant get it done right now. i have all the parts and equipment to diagnose and record reading but what i lack is some welding that needs to be done during the replacement process. you see at 250k miles. mines are all original except the one on the muffle pipe assembly. that was replaced in december 2012 when the cat back assembly was replaced. the others are waiting for my thorley tri-y headers to go on. the remaining three will be replaced then. i did not want to put new ones in and pull them back out again to move them. tho the other post cat one will have to be done that way as i will have to keep the existing cats where one mounts(put a bosch in there 2 years ago and has been giving me issues ever since) a bit longer as i can not afford to replace them right now. and they are worn out chemically.

 

[Goldhawg]

Well, I hit the pick and pull in Cinci today; looking for an 0411 ECM and a Mark VIII fan. Only one possibility in the yard for the ECM (an '02 blazer), and yes it had it. Since I heard that the Mark VIII fan was on Thunderbirds also, but there were no Thunderbirds, I guessed that it was likely on Cougar XR7s as well. So I went to the 97 XR7 that was on the lot, and the efan is 18" across, looks just like the Mark VIII, and has three wires (so this is two speeds if I understand correctly). Out the door for $58 total. So I'm on my way, but this will be a summer job.

 

[Goldhawg]

Can't give individual reports, but yesterday I replaced my old spider injection w/new style, added the ported throttle body, but on the Volant Air Box, and changed rotor/cap/plugs/wires. Overall great improvement; the tahoe is more responsive and I love that it starts instantly (leaking poppet injectors before). Can't say what did what, but I'm happy.

 

[Duckdestroyer]

Does anyone know where to get a exhaust kit for a 99 yukon mine has both pipes that go to a plate behind the cat then you bolt on the other half of the exhaust I want dual and 45° behind each tire.
Hopefully you guys know what I mean by the exhaust plate I don't know what it's called lol

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[SunlitComet]

Does anyone know where to get a exhaust kit for a 99 yukon mine has both pipes that go to a plate behind the cat then you bolt on the other half of the exhaust I want dual and 45° behind each tire.
Hopefully you guys know what I mean by the exhaust plate I don't know what it's called lol

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if you want dual outs it will have to be custom but flowmaster 17166 is a catback for that unit. dual in single out like stock configuration but built better and stronger power wise and with aluminized steel. i use one myself.

 

[Duckdestroyer]

if you want dual outs it will have to be custom but flowmaster 17166 is a catback for that unit. dual in single out like stock configuration but built better and stronger power wise and with aluminized steel. i use one myself.

Ya that's what I figured it had dual 45° out the back when I got it 4 years ago but the muffler rotted out so straight piped it but i don't like the sound of it I want it loud but not that kind of loud lol

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