Search the Community

Hello everyone. Came here with 2022 tahoe GM 6.2 L87 engine problem. 4th cylinder randomly misfires without MIL. When it came to us two months ago it was randomly misfiring by all of the cyilinders, but 1,4,7 were the most. MIL was shown up. Since then we found melted catalytic converter on the left side (1,3,5,7) and changed it. Checked cylinder compression - it is approx. 220 psi (15.5 bar) in every. Changed all of the injectors. Changed all of the spark plugs, wires and coils. All of the spark plugs were completely worn. Now it has only one problem cylinder. It could work without misfire for 1-3 hours staying at idle or start to misfire when accelerator slowly and gently pushed towards to reach approx. 1.5-2k rpm doing 6-25 misfires per logging cycle. No tickling noise. Opened both rocker covers to look at the lifters. They are not stuck when engine is idling. When pushing accelerator fast and completely, or just sharply and briefly push - there are no misfires at all and it stops misfiring if there are some. Total mileage is 25000 miles. 13000 miles ago it had stuck lifter on the right head (2nd cylinder, intake valve). Since then, all of the lifters on the right head have been replaced. Oil pressure is 40 psi at cold engine and 30 psi at hot. Fuel corrections are: -0,5% long bank 1 -1% - -4% - -7% long bank 2 (high percentage when misfires obviously from enriching the mixture with unburned fuel) Short-term correction jumps from 1% in plus to 5-7% in minus, depending on misfires in right bank. Coolant level is constant i guess. Camshaft without any scratches or damages. Could new injector be broken by the chance? Will try to change 4th injector on monday and swap 4th and 3rd AFM system solenoid but it hardly would work. I'll be glad to hear your opinions.

Zane Merva Executive Editor, GM-Trucks.com 5/18/2018 As it turns out, the leaked figures for the 2019 5.3L and 6.2L V8 engines wasn't far off. That's the good news. The bad news is the SAE certified horsepower and torque will match 2018's numbers exactly. But that doesn't mean the 2018 and 2019 engines are the same. Instead of the 2018's Active Fuel Management, which allows the engine to switch between four and eight cylinders, the 2019 V8's have Dynamic Fuel Management. DFM can adjust the firing cylinders in up to 17 different ways. Theoretically, that should mean improved fuel economy at the same power output. Chevrolet hasn't released any fuel economy numbers yet, so that is just a theory. But if you really like the 2018 5.3L V8 and want to buy it again with the 2019 Silverado, fear not. You can option it with a six-speed transmission for WT, LT, and LT Trail Boss trims. -------------------- 2019 CHEVROLET SILVERADO 5.3L WITH DYNAMIC FUEL MANAGEMENT SPECIFICATIONS Type: 5.3L V-8 VVT DI with Dynamic Fuel Management Bore & Stroke (in / mm): 3.78 x 3.62 / 96 x 92 Block Material: Cast aluminum Cylinder Head Material: Cast aluminum Compression Ratio: 11.0:1 Firing Order: 1-8-7-2-6-5-4-3 Valvetrain: Overhead valve, two valves per cylinder, variable valve timing Fuel Delivery: Direct high-pressure fuel injection with Dynamic Fuel Management Ignition System: High-energy coil-on-plug Horsepower (hp / kW @ rpm): 355 / 265 @ 5600 rpm (SAE certified) Torque (lb.-ft. / Nm @ rpm): 383 / 519 @ 4100 rpm (SAE certified) Manufacturing Location Tonawanda Engine Plant, Buffalo, N.Y. 2019 CHEVROLET SILVERADO 6.2L WITH DYNAMIC FUEL MANAGEMENT SPECIFICATIONS Type: 6.2L V-8 VVT DI with Dynamic Fuel Management Bore & Stroke (in / mm): 4.06 x 3.62 / 103.25 x 92 Block Material: Cast aluminum Cylinder Head Material: Cast aluminum Compression Ratio: 11.5:1 Firing Order: 1-8-7-2-6-5-4-3 Valvetrain: Overhead valve, two valves per cylinder, variable valve timing Fuel Delivery: Direct high-pressure fuel injection with Dynamic Fuel Management Ignition System: High-energy coil-on-plug Horsepower (hp / kW @ rpm): 420 / 313 @ 5600 rpm (SAE certified) Torque (lb.-ft. / Nm @ rpm): 460 / 621 @ 4100 rpm (SAE certified) Manufacturing Location Tonawanda, N.Y.