GMC Truck Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi everyone, I'm new to the forums but have been reading them for a while. i have an 03 silverado 1500 quadrasteer 4x4 with a 5.3 cold air intake, stainless shortys, 40 series, bullydog gt tuner, and level kit. all new fluids new trans filter. I've had the truck for about a year now and on a warm day with the ac on the truck is extremely sluggish off the line and not much faster with the ac off. when i got the truck it was completely stock. the mods helped a bit but its still way too sluggish. it feels like its starting off a gear or two high but its definately still in 1st. ive flushed injectors twice, ive cleaned maf. ive vhanged plugs (which helped more than anything) i run super unleaded with the tuner set to 95 octane. ive done everything ive seen on this forum short of twins or a 7.0 swap. the only code that pops is a knock sensor code which hasnt popped in the better part of 2 months. it was popping a misfire code in the second cylinder. havent seen that one in 6 months. anyone have any suggestions?
 

·
Premium Member
Joined
·
2,287 Posts
Hi everyone, I'm new to the forums but have been reading them for a while. i have an 03 silverado 1500 quadrasteer 4x4 with a 5.3 cold air intake, stainless shortys, 40 series, bullydog gt tuner, and level kit. all new fluids new trans filter. I've had the truck for about a year now and on a warm day with the ac on the truck is extremely sluggish off the line and not much faster with the ac off. when i got the truck it was completely stock. the mods helped a bit but its still way too sluggish. it feels like its starting off a gear or two high but its definately still in 1st. ive flushed injectors twice, ive cleaned maf. ive vhanged plugs (which helped more than anything) i run super unleaded with the tuner set to 95 octane. ive done everything ive seen on this forum short of twins or a 7.0 swap. the only code that pops is a knock sensor code which hasnt popped in the better part of 2 months. it was popping a misfire code in the second cylinder. havent seen that one in 6 months. anyone have any suggestions?
I had the same problems in my old truck. Probly knock sensors
 

·
Registered
Joined
·
900 Posts
Is there 95 octane at the gas stations out there?
 

·
// Young & Reckless //
Joined
·
219 Posts
I had that problem til I was driving about 20mph and manually dropped thru all gears. I swear it fixed my problem and I don't know how but it's been great for the past week.
 

·
Registered
Joined
·
3,481 Posts
how warm is a warm day? What altitude are you at. The clutch fan hurts you on a warm day. My tuned 06 ECSB Sierra will roast the tires and lock up the g80 very easily at sea level up to about 96*. Higher temps it will reduce timing and be a little more sluggish. When I went to Albuquerque at 5K elevation it could hardly to a burn out on a dirt road. There are many factors that can affect drivability. Since you mentioned knock sensor, I'd highly suspect that to be part of your problem.

Mr. 960
 

·
Registered
Joined
·
292 Posts
Try bumping the tune down to the next level. If that don't work do the knock sensors. And make sure to silicon the tops of them. Believe there not siliconed from the factory easy for water and dirt to get in.
 

·
Mmm Sandwich
Joined
·
15,700 Posts
Try bumping the tune down to the next level. If that don't work do the knock sensors. And make sure to silicon the tops of them. Believe there not siliconed from the factory easy for water and dirt to get in.
This but put it back to stock and see if the same thing happens
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #12 ·
I even cut the cats off and ran open headers to see if it would fix it. Still runs slow. Actually feels a little slower. Anyone wanna buy a truck?
 

·
Premium Member
Joined
·
2,287 Posts
Bumped the tune back down to stock, made it even worse. Haven't had any codes since I've started the thread
I even cut the cats off and ran open headers to see if it would fix it. Still runs slow. Actually feels a little slower. Anyone wanna buy a truck?
Dibs,

Are you sure the check engine light isnt burnt out?
 

·
Registered
Joined
·
292 Posts
Sell the tuner and get a dyno tune. :crazy:
Tuner will be able to get and idea through the sensor readings too if anythings wrong.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #15 ·
I'm doing an electric fan conversion then a cam in the beginning of next year. I think its just the heat pulling timing then the fan clutch making it harder to run. Runs a lot better with the magnaflow cats. And I'm 100% sure the check engine light isn't burnt out.
 

·
Premium Member
Joined
·
2,287 Posts
I'm doing an electric fan conversion then a cam in the beginning of next year. I think its just the heat pulling timing then the fan clutch making it harder to run. Runs a lot better with the magnaflow cats. And I'm 100% sure the check engine light isn't burnt out.
If its the fan, most of us would have the same problem. It's not the fan. Go through the knock sensor check with a multimeter.
 

·
Registered
Joined
·
292 Posts
If its the fan, most of us would have the same problem. It's not the fan. Go through the knock sensor check with a multimeter.
Exactly what he said. Do not neglect to check the knock sensors. If their bad ecm is pulling the timing.
 
1 - 17 of 17 Posts
Top