I have a 01 rado with the 4.8. My service engine soon light blinks when i get the truck over 4000 rpms, then once it gets below 4000 it shuts off. Then last friday pulling my racecar i brought it up over 4000 rpms it started blinking then it stayed on. I have a cortex programer, so i checked the dtc's and it told me i had a misfire on number 3 cylinder. It does it when i'm not pulling the racecar also. Can you guys help me?
Try some new sparkplugs and fuel injector cleaner.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
wires for sure...mine went to crap at 80k
Vortec Performance Tuned
LQ9 built 4L60 LTs and a billion miles on the speedo!
Also check the plug cap/tip - make sure it's screwed on. Check wire for breaks.
It could be several things...like everyone else said...try the plug, spark plug wire, check for carbon build up at #3, the #3 coil pack, and the injector at #3. The FPR is located on the fuel rail in between the #5 and #3, so it could be a faulty or clogged FPR as well..
2000 ECSB 6.0L
TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's
Did you hear pinging above 4000 rpm?
2001 ECSB 4x4, 5.3, Radix, 3.0 pulley, VHP Trucker cam, 216/224 .551/.551 115 lsa, 1.8 Crane roller rockers, 4L65E, Yank SC3000, 3.73, Cal-Tracs, HPTuners.
Yeah heard pinging, I always run 93 octane and also the lucas fuel treatment in every tank, I just got new plugs, wires, and a fuel filter hopefully it isnt a coil pack there pretty pricey. I appreciate all your help, hope it works Thanks
While you are doing your maintenance tune up, swap the #3 coil with the #1 coil. If it happens again after the tune up, and the miss moved to #1, then it is a bad coil. If it does not move, and is still #3, check your catalytic converter for backpressure. Anything more than 1 PSI at 3000 RPM will cause this also.
Alright i changed plugs, wires, and switched the coils and it has the misfire on # 3 cylinder still. How do you check the back pressure? Or what else could it be?
It is a special tool, similar to a compression tester. You remove both front O2 sensors, screw in the gauge(one side at a time), start the engine, rev up to 3000 rpm, and check the gauge. I borrowed one when I needed one, but I don't think they cost much.
The problem COULD be related to the #3 fuel injector. To find out without spending any $$, you could swap the injector to another cylinder and drive again. If you have a compression tester, you could also rule out an internal engine mechanical problem by doing a quick compression test.
Diagnosis is a process of elimination sometimes. Don't give up.
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