The intake gasket sits between the intake manifold and the cylinder head. The intake gaskets on the LB4 and 元5 vortec’s are very prone to going bad which results in engine leaks, overheating, stalling, etc. Symptoms of Failing Idle Control Valve and Throttle Position Sensor Like the ICV, the throttle position sensor is mounted onto the throttle body and can wear down over time, get dirty, or completely fail.

The throttle position sensor is responsible for reading how far down the accelerator pedal is pressed, and relaying that to the throttle body. Over time, from the large volumes of air that pass through it, the valve can get gunked or clogged up and being to function poorly, creating idle issues. Once you begin to use the accelerator, it opens up allowing full air flow. At idle, the valve blocks a small amount of air from entering the engine, keeping idle RPM’s low. The idle control valve sits on the throttle body and is responsible for adjusting the amount of air that enters the engine at idle, ultimately controlling engine idle speeds. The idle control valve (“ICV”) and throttle position sensors (“TPS”) are prone to failure on all 4.3 engines, which can result in poor idling, engine stalling, bad acceleration, and other low-rpm running problems. Excess oil consumption (primarily on LU3 from 2004-2009).

Engine knock (primarily on 元5 and LF6 1996-2002).

Distributor failure and distributor cap.

Idle control valve and throttle position sensor failure.

However, while these engines are rock-solid for the most part, there are still a handful of common problems worth mentioning. Despite first being introduced 35 years ago, there are tons of these vehicles still on the road today. The 4.3L Vortec is the longest living and most successful of the Vortec engine family. As you can imagine, engine technology has progressed significantly since 1985. While the general make-up of the engine remained the same over its production history, the engine revisions upgraded and changed many components and features over the years. 元5 (1992-2002 in C/K, Blazer, Silverado, Sierra, and others) LB4 (1985-1995 in the S10, El Camino, and other non-truck vehicles) Over its nearly 30 year production history the 4.3L Vortec went through a number of revisions and upgrades: The 4.3 Vortec engine (or Vortec 4300) is a 6-cylinder small-block that was introduced in 1985 and continued in production until 2014. Chevy’s vortex technology creates an air vortex inside the engine, which results in better air-to-fuel efficiency. The term “vortec” is simply a marketing name used by Chevrolet to communicate its use of “vortex technology”. The Chevy vortec engine line spans from small block V6’s to big block V8’s and also includes some inline 4, 5, and 6 engines used in less popular GMC brands.

Hit and miss engine coil wiring diagram