2000 5.3 idles rough and struggles in cold weather

Chevyboy2000 · November 4, 2024

I have a 2000 Silverado that idle like ****** in cold weather like 45 degrees.it always turns on she runs then the check eninge light blinks I try to drive off but It wants to stall I drive in the check engine stops blinking.I changed the MAF SENSOR AND COOLANT TEMP SENSOR if anyone can help I would appreciate it.

CamGTP · November 4, 2024

What code is it throwing?

Shot gunning parts at it isn't a good idea. The flashing check engine light should be telling you what to look at. Could need an actual tune up. Like fresh spark plugs, cleaning the fuel injectors, changing the fuel filter. Cleaning the throttle body and IAC valve too.

Tickerguy · March 23, 2025

Check the fuel trims. If you are lean (very HIGH trims) at idle, especially when cold, but with some throttle (or when running) they are lower or near/in the normal range on BOTH banks I'll bet your intake gaskets are leaking (badly.) This problem tends to be materially worse the colder it is outside, especially on a cold start. When it gets especially bad the engine will not run at idle when its cold out unless you give it a fair bit of throttle.

BTW this is a "must-fix" because you are ingesting UNFILTERED AIR which means you're greatly accelerating engine wear. Do not ignore this; CLEAN intake air is LIFE, second only to clean oil under pressure.

Pretty common problem and not all that hard to fix -- I recommend using the FelPro set, its of better quality than OE and no more expensive. I've had to change them on a couple of these engines; while you have the intake off check the knock sensors under the manifold and if there is ANY indication of water intrusion in there replace them both, the harness to them and the plugs -- and seal both with silicone. It BITES if you wind up having to remove the intake a second time to replace the knock sensors!

Do use some care when taking the intake off as there is often quite a bit of debris in that area between the intake and the head and you don't want it going down an open intake port!