Hello, I just bought a 94 Suburban 5.7 4X4. 123k original miles carfax certified. This suburban has been very well taken care of. It has a lift, nothing crazy with 33" tires. The truck runs very well but I just know that there is more power to be had. There are no modifications under the hood. I am not looking to hot rod the thing. The truck has sat a lot during its life. The sticker in the window for the next oil change showed I has 1200 miles to go before I hit the 3k mile mark and it was dated 2012. I wanted to know what I can do to get more power. I notice from a stop it goes pretty good but when I hit the freeway and it starts getting the rpms up there a little it just kind of stops gaining power all together and eventually drops a gear and will get to the speed I want but it really is sluggish. People say it has big tires and those engines aren't fast and blah blah. I know it has more then that. So I thought I would give it a tune up with performance plugs and wires for a start but where do I go after that? I don't want to add 100 hp. I just want it to not stop gaining power at higher rpm's on the freeway. Thanks in advance!

 

Check your gear ratio
GU4 - 3.08
GU5 - 3.23
GU6 - 3.42
GT4 - 3.73
GT5 - 4.10
HC4 - 4.56
G80 - Factory limited slip


YOu describe an engine running out of power or gears.


DO your basic tune up first using factory type parts....don't use split fire plugs etc.


SHoot for basics like air/intake fuel/ exhaust.


WHat gears do you have?

 

Welcome to the forum.

Use AC Delco plugs. Check compression.

These engines don't have a lot torque in the higher rpm range and you're talking about a almost three ton truck. You might check out BlackBear Performance and/or Procharger for more power.

 

Thats exactly what happened when my tranny went out.....