for info archon,

i take a look today during my 30 minutes brake at the shop,

i dont think it is my plug, on idle i can see small brown smoke out of my tips.

The worst "miss" are when i move the car slowly from a standing stop, or at WOT

Today i tried to disconnect the sensor under the thermostat. The car seem quicker in response, i tought was a good new til i slow down, put in reverse and start again to miss.

But the car seem to have better response with that sensor disconnected.

Any info on how to wash a Mass air flow?
step by step.


Ill try to wash the MAF, if it doesnt help ill change my o2 sensor, what do you guys think?
I dont want to waste 150 $ for a diagnostic to the dealer in addition of a 150$ o2 sensor.

Its clear that i run too rich with that brown smoke at idle.

You should have the car scanned for codes. Some codes do not light the SES lamp.

Possible problems could be...

Plugs
Wires
ICM
Crank position sensor
Front 02 Sensor
Clogged cat
low voltage from the alternator

Mike,

You'd better PM me your phone number during the day. I could try to arrange for Jerry (the guy who did your pulley) to scan your car during the day because he'* not far from where you live.

I also have a used but good AC Delco O2 sensor that can be used for testing.

Cheers,

Thx Paul, ill PM you my phone number, Friday i finish work at 12:00 PM so after that i can meet you or jerry, or saturday, like you want.

Thx also Rogue for additionnal info.

***UPDATE***

I got the car scanned this morning, here are some of the result(lost the log)

(BEFORE RESETING THE PCM)
- MAF sensor "ok"
-KR "0" ( 0.94was the higheri saw)
-couple of misfire cylinder 2-3-4
-rich mixture
-long term fuel... -25 or -22
-short term.. -22 or -25

thats what i remember.

(AFTER RESETING THE PCM)

-MAF sensor "ok"
-KR "0"
-misfire "not at all"
-long term fuel
-short term fuel...__ at 40% throttle its fine 0 and -12 and -20\-19 at cruising.
-Spark advance___ " 7 at low throttle 30-33 at idle and 7-8 at WOT and then black smoke"

(o2 sensor testing was not available on the test.)

it seem like that my spark (or spark advance) fall when i touch the throttle , even a small push. i keep spark over 30 at idle and go down to 7-13 when accelerating, at WOT the spark cant take all that fuel and then a black smoke come off my tips.

From the scan, everything is fine except the spark, and only the o2 sensor test was not available (in the possible failure) and the crankshaft.

Can a bad o2 sensor can make the PCM drop the spark??
at idle am ok, but not on throttle.


I hope its just the o2 sensor and not the cranshaft sensor, or i will say goodbye to my 1.9 rocker

Anybody have an idea on what can drop the spark that low?



note: A big thank you to Foghorn and his friend Jerry for scanning the car.

Mike

EDIT: I just called a place, i can have one o2 sensor today, but its an NGK universal one, is it good enought?

Just bought a new O2 sensor...204$ canadian...grrr.., i will install it tomorow to see if thats my problem...
I hope! :? ive talk with a GM mechanic today and he give the same options as Foghorn said, O2 sensor or crankshaft positionning sensor.


Please pray for me guys

Mike:
Here is hoping that your first corrective action fixes the problem.

Do i need to reset the PCM after installing the o2 sensor?

or it will adjust after some minutes by itself?


Thx

No need to reset the PCM for an O2 change. I hope you bought an AC Delco one because the others are of lower quality.

Sorry I couldn't have been of more help to you on Saturday Mike, I'm in major renovation mode at home and spent the day installing new ductwork in the attic!!!

I did mention to Jerry I had a spare O2 sensor you could use for testing, cheaper than buying a new one. I was a little concerned to hear Jerry did not even have the option of monitoring the O2 using the Powrtuner...that indicates a problem to me because he has scanned your car previously and all options were available.

If you haven't installed the sensor yet you're still welcome to borrow mine for testing!!

Cheers,

THx! may be i should try with yours to check it and may be i can return the new one to GM if its not the problem.(and its an AC Delco)

And for the o2 test... tell me if im wrong but i think it was your scanner for the previous test because Jerry had problem with his Tuner..?

Just let me know how we can arrange if i use your o2 for testing(what arrange you the best), the car really need to be fix. I hate how it run right now :?

...You think my PCM may be have trouble?

Edit: And dont worry, you help me a lot, at least thats a big deal for me to get my car scanned for free