Idle rough/ Engine miss looking for anything I have missed

[Ratical2]

Hello All,
I am looking for a little help. I have done a search and can't find anything that quite addresses what I am experiancing. I have a rough idle and miss that is more pronounced when cold butis still noticable when warm.

The engine idle varies from a Lubity, lubity, lubity, (with the car rocking side to side) to jolting blatt, blatt,blatt and repeat.

It is almost as if the engine is fighting itself. Basically, the engine is 2 in-line 5 cylinder engines that share a crankshaft. How can I be sure that both sides are working together?

I replaced the spark plug wires (MSD) and plugs about 3 K miles ago and it did help but the the symptoms were not totally gone. Now they are becoming more pronouned again.

I have checked to see if the butterfly valves are opening at the same time and they seemed to be.

Things that I could do:
Replace wires and plugs again,
Clean fuel system
replace O2 sensor( I believe it is original)
run a scan

Anyone have any ideas?

This a 96 GTS with 23K miles as of today.

Thanks!

 

[dave6666]

Clean your idle air thingy.

Sorry. It's early.

Also...

Reset PCM.
Bad fuel?
Clean injector connections.
Properly sync TB's?
Battery age?
Clean PCM connections.
Fuel filter?

 

[bvk]

ah yes, the idle air thingy. I need to clean my idle air thingy.

 

[Jack B]

Get a scan tool and verify, the O2 voltages. Even a cheap scan tool can log both O2 channels. You can also look at the LTFT on bank 1 and bank 2. This will probably lead you to the malfunctioning side. You should also pull all ten plugs and number them, then, compare and see which cylinder(s) vary from the norm.

 

[Ratical2]

Thanks for the suggestions. I will try them tomorrow.
Run Scan- Pay attention to 02 readings. Replace sensors if neccessary
Check Charging System and Battery condition
Replace fuel filter- More than likely original.
Pull and inspect Plugs.
Clean appropriate connections.
Fuel injector Cleaning?

These symptoms are subtle but my wife noticed the difference when I changed the plugs and wires so it can't too subtle.