So I ended up getting a really good deal on a '97 Chev heavy duty 3/4 with really low miles. Its an extended cab 4x4, with a 454, auto trans and 4.10 gears. I preferr Fords and have three Superdutys for our bussiness that we have had excellent luck with but this truck was so clean and for the price we couldnt pass it up. The truck seems like it has pretty good power so I expected it would tow a 7,000 pound trailer some what decent, I pulled over parleys at 19 mph. I thought maybe a plugged fuel or air filter so I did a full service and it didnt help. I ran a few bottles of injector cleaner through it and that didnt help either. I thought about running a powerchip but I would preffer to only have to run low to mid grade gas. I also thought about maybe running 4.56 gears. What would you guys suggest.
Truck is gutless
- Thread starter oxbronco
- Start date
- Location
- Bountiful, land of rocks
Being a Vortec 454, that thing should at LEAST do 40 over Parleys. All of those I've seen run quite well but like to chew the fuel. There's got to be something wrong.
rholbrook
Well-Known Member
- Location
- Kaysville, Ut
Could be the catalytic converter is getting restricted. I have had 2 vehicles have that problem and one of them had low miles. What a difference it made.
Mope
Registered User
- Location
- Pocatello, ID
x2 on the cat
O'neal
?????????
- Location
- evanston wy
I used to pull my old runner with the wife's uncle's old truck 98 vortec 454 auto 100k+.It would pass anything but a gas station.Pulled an old car + lot's of scrap iron 4500lb over parley's last summer and if I recall it pulled 55-60 with the OD off,Damn good truck.
I would say something is wrong also,it should do better.Have to agree on checking the cat.....
I would say something is wrong also,it should do better.Have to agree on checking the cat.....
Mine is a 99 crew, 454, auto, 6.72 gears, 46" tires. Stock engine and trans.
My truck is geared like a 4.10 truck with 28" tires.
I do have true dual 3" exhaust, but it didnt seem to change much for me.
I weigh in at 8600lbs empty, and over 17,000 loaded. Trip to moab, I never dropped below 55.
I would say something is choking it off.
My truck is geared like a 4.10 truck with 28" tires.
I do have true dual 3" exhaust, but it didnt seem to change much for me.
I weigh in at 8600lbs empty, and over 17,000 loaded. Trip to moab, I never dropped below 55.
I would say something is choking it off.
RockMonkey
Suddenly Enthusiastic
I'd check the cat too. Is it rattling?
Sometimes when a cat goes bad it starts rattling as the inside start breaking up. I have had one rattle which restricted the flow and I have a one just plug up with no rattle.
I will check it out tomorrow and let you know, I usually run at least mid grade gas when towing, it seems like with these newer computer controlled engines you can get away with running a lower octane fuel and not get any pre-igniting. I hope it is a cat or muffler problem. Running light around town the truck runs great, even towing it seems to be running good just no power.
- Location
- Smithfield Utah
x500 on the cat. 7K behind that Vortec should be no stress.
I would also look into a less restrictive exhaust altogether. 3" single from the manifolds back should work great, and if you choose to go dual an H-pipe will really help you out.
How does your transmission act with the load? Is your torque converter locking up? If not that can suck power. Was your engine temp getting close to red? If your engine runs hot then your trans will too...
Also a stuck fan clutch can rob power (maybe not that much) is your fan on all the time?
I would also look into a less restrictive exhaust altogether. 3" single from the manifolds back should work great, and if you choose to go dual an H-pipe will really help you out.
How does your transmission act with the load? Is your torque converter locking up? If not that can suck power. Was your engine temp getting close to red? If your engine runs hot then your trans will too...
Also a stuck fan clutch can rob power (maybe not that much) is your fan on all the time?
For the exhaust. My truck came factory with dual 2 3/4" from the manifolds to the muffler, then single 2 3/4" out the back.
Single 3" from the manifolds back would only be an improvement over the tailpipe.
But your truck may have a more restrictive exhaust than mine had from the factory.
Single 3" from the manifolds back would only be an improvement over the tailpipe.
But your truck may have a more restrictive exhaust than mine had from the factory.
The trans shifts great, and the temp didn't get above 220. I had master muffler install a new exhaust today, I kept the stock Y pipe and installed a new 3'' high flow cat, and a magnaflow 3'' straight through type muffler. The power feels a little better than before but not alot. I guess I will have to do a tow test and see how it does. Sure sounds good now. Also wouldnt a plugged cat throw a engine code, my dad has a 2006 GMC with a 6.0 and he got a code when one of his cats plugged.
There arent any sensors (on my truck at least) that monitor back pressure, maybe a bad reading on an o2 sensor would trigger something.
Your truck has single 3" exhaust?
Here is a picture of the factory exhaust on mine. The new pipe starts where the old muffler was.
Your truck has single 3" exhaust?
Here is a picture of the factory exhaust on mine. The new pipe starts where the old muffler was.
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