Loss Of Power

[DUK5]

I wanted to know if yall could help me? I have a 1990 k5 blazer I lifted a year ago a put 33" tires on it, since then I have lost power hard as hell to get up to 70mph it has stock front and rear diff with 373 gears.The trans in good shape and engine is strong do yall think I need to re gear the diff if so what ratio? Any advice would be help full thans Jayson

 

[BIG*RED]

Thats hard to say, i would think that there is another underlieing issue hear, because im running 8 inches of lift with 37 inch tires, with 3.73 gears and i can easily hit 70, and beyond, and i can do so fairly quickly. IMHO 33 inch tires with 3.73 should not cause that much of a loss of power....

 

[Drey]

3.73s and 33s should be in the realm of not needing to regear. Do you have a 305 or a 350? Also when was the last time you did a tune up?

 

[DUK5]

I have a 350 with a 700r trans did tune up last month

 

[BIG*RED]

A thought that i just had....you running a cataletic converter? if those get clogged up, it could result in a loss of power...

like stated before, your tire size and gear ratio should not be whats causing the lack of power

 

[Drey]

Replace the 02 sensor, make sure the cat isnt plugged...or ditch it if you live in a non-hippie state.

 

[DUK5]

No cat true duels, what else should I check

 

[gone huntin]

Did you replace your fuel filter when you did the tune up? If not, try that

 

[80' 427]

fuel filter, air fliter, compression, timing (8 int work awsome on a stock tbi), fuel pressure.

 

[Drey]

Plugs, Wires, Cap & Rotor, O2 Sensor?