Silverado 5.3 L is misfiring
My Silverado has a misfire when a
load is put on the motor ie going
up a steep grade or hill. Cruising
down the highway at 55 mph,
transmission in overdrive, the
rpm's drop to around 1500 or 1400
the motor starts misfiring. I
usually drive with the cruise
engaged and if the rpm's drop any
further it will kick into passing
gear and everything smooths out.
If you put your foot in it, the thing
will spit and spat and even
backfire before you get up enough
power to pass or finish climbing
Get this, I got someone to connect
a code reader to it. NO CODES! I
replaced the fuel filter under the
cab. No good.
Do I have a bad spark plug? Bad
plug wire? Or do I have an internal
problem that the truck computer
brain will not pick up?
Has the check eng light ever come on while it's acting up
Check engine light has never come on. I get the usual like, change oil, low washer fluid, low coolant and such but no check engine.
you're going to have to have a scanner hooked up while it's doing it then you can see live What cylinders are misfiring.it is a 5.3 and not a 5.7.right just making sure
5.3, that's the 327 I believe and the 5.7 is a 350? I have a 5.3 according to the vin#
Need that scanner .you will save way more money that way than guessing
How much for one? I've never priced them.
If your Silverado has over 100,000 miles on it you're due for a tune up. If the engine is truly misfiring under load the check engine light would be on or flashing. Try the tune up, if you're due for one and go from there. To me it sounds like an ignition problem. HTH. -Jim
That was my first guess but it's a little strange that the check engine light or any codes haven't come up. Anyway, you are correct, it is due for a tune up. Thanks for your help Jim and sagomonkey! I appreciate it! Think I'll start doing a little customizing now.
You're welcome. Glad to help. - Jim
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