I've got an 07 impala LS 3.5L V6. Car has a rough idle.... RPM's drops down to 550 to 600rpm once it reaches operating temp and it has been driving in stop and go traffic like when commuting to work.
So problem is this rough and low rpm idle
that drops to 550rpm once stopped at a red
light but when I run the a/c the idle comes
up to the normal for that car at 700rpm
however this rough idle is still there. So I
replaced the plugs, wires, cleaned the mass
airflow sensor and throttle body thinking
that's my issue, well the idle started to
rocket to 900 to 1000 rpm but that's
because I disconnected the battery and
unhooked the sensors when I did my
cleaning the computer needed to relearn it's
factory idle preseting. Car drove great for a
week, then idle was normal and before I
knew it that rough idle came back. Guys I'm
stumped....NO CHECK ENGINE LIGHTS.....
maybe my exhaust ? Catconverter? Or
exhaust hanger or loose bolts cause the
vibrations? What gives? Maybe an early
failing stage for my 02 sensors?
Ok after living with that issue for 2 months finally got the problem solved. It was 2 items that were compromised. 1st being my power steering pump was in the beginning phase of seizing and failing. The pump began to create a rotational drag on the serpentine belt due to the resistance because the pump was seizing. That brought down the idle. 2nd was the bottom motor mount was completely shot I'm talking about there was no rubber what so ever. Replaced the serpentine belt, power steering pump and the motor mount and the car drives really smooth and quite. Car idles at 700rpm.
Ive been having this same problem with my 08 impala when im on the hwy it only gets me up to about 60 and i have to keep accelerating to get anything higher
Is it the battery?
It wasn't the battery, believe it or not I wrote that problem with that car about a year ago and solved it if you look and read out on my 2nd response. Fortunately, I am now the proud new owner of a new 2015 impala.
How did you determine it was your steering pump
I determined that by 2 reasons. Power steering was getting a whining like noise much like it does when the fluid level is low but that wasn't the case the pulley was actually in the beginning phase of seizing up creating the whining noise and 2nd the bottom motor mount was shot completely deterioted so the motor was actually moving in the engine bay even at idle. Replaced both components and problem solved.
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