Sputter at idle

[giantkeeper]

OK guys it's time to ask what you think.

My car runs great...with a single exception. It has a slight sputter/miss at idle which sits around 750. It has had this symptom since the first time I started the car after the swap. I have noticed it will still do this up to about a 2500 RPM free rev.

I currently have about 1500 miles on the swap at this point with no change in condition.

There does not seem to be any real effect on the car. Power delivery is strong and smooth, but I am concerned that if left unattended it could lead to other issues.

No codes, no vacuum leaks, pulled the plugs and they looked OK and it's running a TRM tune.

Any ideas before I take it to my indy guy to troubleshoot?

:dot:

I appreciate the assistance, thanks!

[giantkeeper]

[e46s54dr]

Is the symptoms present only when the engine is cold or is always sputtering at low idle even at running temperature? Also what is it idling at?

[giantkeeper]

Is the symptoms present only when the engine is cold or is always sputtering at low idle even at running temperature? Also what is it idling at?

It sputters consistently hot or cold. Idle is pretty solid at 750....

[Jalves619]

Have you tried running the 3" MAF and factory chip to see if the sputter is still there?

[giantkeeper]

Have you tried running the 3" MAF and factory chip to see if the sputter is still there?

No, I don't have the 3" maf anymore :(

[samiam3356]

check TPS and clean ICV. check back

[matt]

It's not detonating at idle. I think you mean misfire.

You probably have an air leak after your MAF.

[giantkeeper]

It's not detonating at idle. I think you mean misfire.

You probably have an air leak after your MAF.

Right, misfire sounds accurate. I'll take it to my guy and smoke test it. I did the "carb cleaner" test and was unable to find any leaks.

Thanks Matt!

[giantkeeper]

Smoke tested the car today - no leaks.

[matt]

Next, I would try replacing the spark plugs with new ones and test all your coils.

Does the problem change if you put your foot on the brake? I've seen boosters that only leak when you press them.

[giantkeeper]

Next, I would try replacing the spark plugs with new ones and test all your coils.

Does the problem change if you put your foot on the brake? I've seen boosters that only leak when you press them.

Thanks Matt - I'll swap the plugs this week and test the coils.

No issues with the booster at this time, although I did have a leak at the booster inlet plug initially.

[Zba]

Check your o2 sensor for functionality

[giantkeeper]

Swapped out the 1500 mile NGK plugs and dropped in Bosch OEM replacements yesterday. No change in condition.

[giantkeeper]

Update - drove the car to work today. The idle is lower, but there was far less sputtering. When I finally got home it was non existent.

We shall see how things go the rest of the week...and on the dyno Saturday.