Low Speed Surging (Soft).

[motorhead]

Basically, while cruising below 1700 rpm the car surges ever so slightly. I have only been driving her for a few days now (fresh to road use) and it is becoming more noticeable as I become acquainted with the car.

My IAC is ~39 (I know it needs to be in the 18-22ish range), and it will be rectified later today. My O2s are on the rich side of 800.

What could this be attributed to? And how can I fix it?

Thanks,

 

[subtlt]

Injectors

Your injectors need to be cleaned/replaced depending on mileage. You'll find a whole host of issues go away with clean injectors. If you're going to have them cleaned, find a shop that has a Sun Motorvac system - it does a terrific job.

 

[TurboDave]

Originally posted by Mr. T
Basically, while cruising below 1700 rpm the car surges ever so slightly. I have only been driving her for a few days now (fresh to road use) and it is becoming more noticeable as I become acquainted with the car.

My IAC is ~39 (I know it needs to be in the 18-22ish range), and it will be rectified later today. My O2s are on the rich side of 800.

What could this be attributed to? And how can I fix it?

Thanks,

What speed does this happen? could be your torque converter locking and unlocking.

 

[WarpSpeed]

I think he has a non-LU, Dave.

Could be an post MAF air leak maybe,, pre-turbo exhaust leak,,, or maybe plug wires....

 

[motorhead]

Re: Injectors

Originally posted by subtlt
Your injectors need to be cleaned/replaced depending on mileage. You'll find a whole host of issues go away with clean injectors. If you're going to have them cleaned, find a shop that has a Sun Motorvac system - it does a terrific job.

The injectors have less than 5000kms (3500ish miles) on them... I doubt this is the direct cause. I have done a search (duh, I know... search first, ask second) and learned that it could just be low FP at idle. It is currently set at 41psi... and the EGR is working fine, as my car just did emissions and nearly read zeros across the board.

The plugs are gapped to .035" and are the AC '43s.

Could I be missing anything else?

The joys...

 

[motorhead]

Originally posted by WarpSpeed
I think he has a non-LU, Dave.

Could be an post MAF air leak maybe,, pre-turbo exhaust leak,,, or maybe plug wires....

Yeah, it is a non-LU POS.

There is an new solid MAF with the silly cone hoses... But I can tighten the clamps. Screwdriver time.

The DS header has been welded up recently... however, I am sure there are other places to look. Like the torque to the head.

The plug wires are B/N with under 600kms on them... Unless MSD shipped me some lemons. Time for a ohm meter.

Keep 'em coming

Thanks.