Another Strange Problem.

[Test4echo]

This is what I've done.

New Upper, Lower intake gaskets.
Cleaned IAC, Pintle and spring, reset Pintle lenght to proper lenght from base.
All new plugs (not wires)
New PVC
Checked for vaccum leaks
Checked all sensors using scanner. All read within specs.
New EGR gaskets, includign adaptor.
Fixed o-ring leak.
02 tested, for proper open/closed operation

Ok, symptoms:

Turn car on,
Runs great, Idles well, no flux while in N,P or Drive.
Accelerates awesome, no hesitation.
Even letting off the gas quickly while at High RPM, Idle returns to around 1100-1250 nicely. Complete stop, its comes down to around 850-875.

Then about 20 minutes into engine on,
I notice some muffler spitting sounds, ( missing?)
Idle gets erratic at all RPM's and car speeds.
Exhaust smells (not rotten eggs)

The scanner reports a fight between rich/lean conditions.
The ecm is constantly trying to compensate for the problem.

About 1 minutes to 2 minutes after I begin to have those symptoms mentioned above, the SES trips and its a Code 44 ( Lean Condition).

Strange part is, Immediatly after the SES light come on, the car seems to fix itself and begins to run like a dream.
It runs great for the rest of the trip.

However, once the car has been turned off, I have to through this all over again.

I can pretty much predict when the erratic idle will occur, and it always goes away once the SES light comes on.


What could be causing this very predicatble issue?

Thanks,

[SappySE107]

rich/lean is normal and good, it shows the O2 sensor is working. It sounds like the EGR is messin up to me, but id have to see a scanned log.

[Test4echo]

SappySE107

SappySE107,

I have a log saved, and I have a scanner. Snap-on mtg2501.
What would help to pin down the egr as the problem? As far as what reading to take a peek at?

Thanks,

[SappySE107]

Well, its hard to guess at this point but I would look at the BLM and INT before, during, and after it acts up. I would also look at the TPS and MAP/RPM to see if its wherethe EGR could turn on, plus what the coolant temp was when it first acts up.

When its running and warmed up, how fast does the O2 voltage change? can you read the numbers or does it move to fast to really get a solid look at any of the voltages.

[Test4echo]

Cool

Car on, Idle

BLM hovers around 128, Plus or minus depending on RPM.

A/F ratio is 13.7 - 11.3
IAC postion is 51 at idle
TPS is 0.52
Start CLNT 171F
MAP 101
MAP (V) 4.94-1.96 (depending on RPM)
Baro 101
RPM 850

O2 voltage fluctuates very quickly,
In live graphics mode, rich/lean conditions moves way to fast to pinpoint.
So I figure 02 sensor is doing its job.

ANy help?

[SappySE107]

Your MAP is way off for idle, as is the AF ratio. MAP should never hit WOT condition at idle. Is that fully warmed up?

[93vinx]

iac should be around 20 rite? at warm idle

[Test4echo]

Drove all day today, didn't hiccup once.
No SES light either.
This problem has me perplexed.


However, I did see another leak though.
Haven't checked to see if it was oil, tranny or PS yet.


test,

[SappySE107]

IAC could be anything depending on how clogged up the passage is with carbon, vacuum leaks, air past the TB... As long as its not 0 its ok.