RPM jump coming to stop / Random engine shut off / Cold start misfire on all cylinder

[AWDrift123]

Hello,

 

I have three things that's been bothering me and I've done much research but I could use some inputs.

 

Car Info: CAI/Uppipe/Downpipe/CBE/DW65c Pump/E85/Stage2 Tune

 

These are things I'm noticing...

 

1. When I'm in neutral and coming to a stop, as I am just about at complete stop, sometimes my RPM jumps up to about 1.5k then goes back to normal.

 

2. While driving on highway, from 5th gear cruising around 50-55mph, I go in neutral and engine died (twice so far, months apart). Engine starts fine (having to start while driving it "dead") and no CEL or codes, then drives fine.

 

3. When starting the car in the morning, few times (months apart) it did not want to start and when it did, it threw CEL, code (misfire all cylinders), and cruise was flashing. I used AP to reset the ECU and car was back to normal.

 

 

My thought at this point is that issue #1 might be dirty throttle body, I did do some dirt road "rally" driving following a car pretty closely few months back.

#2 maybe related to throttle body as well? sometimes my A/F reading seems bit positively high so I tap the gas and it returns to normal.

#3...maybe it's just E85 having hard time starting in cold, but I don't know enough to be guessing.

 

 

I am only seeing these issues very randomly but I still would like to know the possible causes.

 

I would greatly appreciate your (pros) input on these issues!

[Max Capacity]

Have you cleaned the MAF sensor lately? should be done yearly with MAF cleaner from the auto parts store.

 

Have you cleaned or replaced the air filter ?

 

These older cars are also known to have bad o-rings at the intake manifold to TGV's, they should be replaced with the new larger orange o-rings, when you see the old ones next to the new ones you'll understand.

 

The front O2 sensor may be getting old too, they don't last forever. Replace it with a new OEM unit. My aftermarket front one only lasted 2 years.

[AWDrift123]

Thanks for input

 

I have cleaned the MAF, that was my very first guess after "rally" driving.

Then it was natural for me to wash and recharge the intake filter...still same although car did seem to breath better (filter was pretty dirty).

 

Is this what you mean by replacing O-rings?

---> http://legacygt.com/forums/showthread.php/diy-rough-idle-cold-start-cold-temps-lgt-07-09-155325.html

 

I shall try this first! seems easy enough

[Max Capacity]

Yes, while your there tighten all the gas lines.

 

I think its may be easier to pull the gas lines from the shock tower, remove the four long bolts on each side at the TGV to head then replace the o-rings on a bench.

 

Though I did mine with the intake manifold on the car years ago before I replaced the short block and pulled the whole intake with the TGV's.

 

see my click here link for that job.