Noticed 5.3l Has Rough Idle At A Stop Light

iceman1998 · September 30, 2011

I have a 5.3L '07 Seirra new body style......i've been noticing that when i'm at a stop light waiting for it to turn green my truck has a bit of a rough idle or miss it seems....tried new plugs, plug wires, good gas....any ideals?

desrtrat · September 30, 2011

a good cleaning of your TB will help, and can of Sea Foam in the fuel tank

empirezclub · September 30, 2011

I just had this but I see you already replaced plugs and wires. Mine was doing the same thing and I replaced my E3 plugs with the factory AC Delco iridiums, changed the plug wires and I cleaned the throttle body with sea foam deep creep. it worked its been a week and so far no more miss at idle. I wish i would have done one at a time to see what the culprit was. I have 76,000 miles on mine and the throttle body had a film of dirty oil on it. i took the throttle body completely off and sprayed alot of Sea Foam in the intake. I let everything sit while I changed the plugs and wires after hooking up and reinstalling everything it fired right up. I was told that if you disconnect the throttle body before cleaning it you wont have the idle relearn problem that takes alot of miles to accomplish! I heard that you should never touch the throttle plate in the throttle body while its plugged in. I have heard of alot of other things that fix this issue too so hopefully someone else will chime in.

desrtrat · September 30, 2011

i would put money on it, if i had any.. it was the E3 plugs. a lot of people have had issue misfires, rough idle after installing them. LS motors just don't like them. stick with AC Delco plugs/wires..

lineman · September 30, 2011

I have the same issue on my 2000. Would any parts place have that sea foam?

txab · September 30, 2011

I have the same issue on my 2000. Would any parts place have that sea foam?

Yes. Autzone, Advanced, etc...

desrtrat · October 1, 2011

I have the same issue on my 2000. Would any parts place have that sea foam?

Yes. Autzone, Advanced, etc...

i get mine at WalMart. a bit cheaper than the auto parts stores. sometimes almost $2.00

iceman1998 · October 1, 2011

OK guys i'll try cleaning the TB again and see it that fixes it!

RockySierra · October 2, 2011

Noticed the same problem in all 3 5.3L trucks I've owned, a 99, 07 (brand new) and 05. Throttle cleaning and sea foam and new plugs and wires and other stuff never did cure it, I just learned to live with it. Seems to be normal.

RockySierra · October 2, 2011

Noticed the same problem in all 3 5.3L trucks I've owned, a 99, 07 (brand new) and 05. Throttle cleaning and sea foam and new plugs and wires and other stuff never did cure it, I just learned to live with it. Seems to be normal.

empirezclub · October 3, 2011

i would put money on it, if i had any.. it was the E3 plugs. a lot of people have had issue misfires, rough idle after installing them. LS motors just don't like them. stick with AC Delco plugs/wires..

Lol, yes the E3 plugs were the culprit. After putting the iridiums back in my fuel mileage went up too. Its funny these engines run perfect and they don't need fancy plugs!!! Just the factoru iridiums!

desrtrat · October 3, 2011

i would put money on it, if i had any.. it was the E3 plugs. a lot of people have had issue misfires, rough idle after installing them. LS motors just don't like them. stick with AC Delco plugs/wires..

Lol, yes the E3 plugs were the culprit. After putting the iridiums back in my fuel mileage went up too. Its funny these engines run perfect and they don't need fancy plugs!!! Just the factoru iridiums!