[turtlepower]

Experiencing extreme rough idle, car fails to start 1/5 times, check engine light on.

The problem occurred my on morning drive to school which is 10 mins city driving. The car had been working fine beforehand , never had any idle issues. I noticed that morning while warming up the car I felt a 3-5 misfires , I drove along to school and I was approaching a hill so I gassed it and all of the sudden the engine felt like I was running on 2 cylinders. Heavy misfire and hesitation, it was so bad I had to park the car and catch a ride. I have been using Lucas gas treatment 3 tanks in a row.

However I came back 7 hours later and started the car , ran smooth! Halfway back to the house the car acted up. Towed car to friends house and then...

Upgraded to TD-04, replaced spark plugs,fuel filter,performed engine flush and removed small quantity of sludge,throttle body coolant by pass, new PCV version,installed a new rubber antenna.

Started the car, wow amazing performance however after 10 mins of driving the car it stalled,failed to start once,rough idling came back( just as bad as the 1st encounter).

I thought of CPS,MAF,O2 sensors,Throttle Body,DIC,bad gas?

The DIC emits spark as I tested it out by plugging the sparks in and grounding them with a wire, crank and all four cartridges fire. BUT, looking at Chamber #4, there appears to be a small amount of fuel coating the piston left unburnt.

Leave the car alone for a few hours start it back up and it idles fine (in park) until you REV the engine or give it load it goes back to the same issue.

Here is a quick video of proper revving and then a stall and a delayed start with a crank. Notice the noise is engine tap not misfire on the 1st run. http://www.youtube.com/watch?v=Zh9W9EW4nhI

I do not have a code reader at the moment.
What is going on?

 

[earthworm]

Good on doing the service work.:cheesy:
Now to the troubleshooting.
A failing CPS , when cold may yield good readings, when warm to hot, it will cause the engine not to run.
A failing O2 sensor, the lambda unit, will trigger a CEL and the MPG will drop. The engine will continue to run, as the ECU will go into default.
The MAP ? I do not know.
We do seem to have a weak spark.

 

[turtlepower]

Good on doing the service work.:cheesy:
Now to the troubleshooting.
A failing CPS , when cold may yield good readings, when warm to hot, it will cause the engine not to run.
A failing O2 sensor, the lambda unit, will trigger a CEL and the MPG will drop. The engine will continue to run, as the ECU will go into default.
The MAP ? I do not know.
We do seem to have a weak spark.

It cannot be the lambda unit for the car has always had great MPG, and it will not cause the car the react this way.

The CPS is something I feel strongly about because of the symptons, especially if you were to know the symptoms of a failing CPS, http://en.wikipedia.org/wiki/Crankshaft_position_sensor scroll to the very bottom.

I am also pulling to the weak spark, it catches my attention. Is there a way to effieciently test the DIC? I've tried calling shops to let me borrow one on deposit but no results.

So 2 things, CPS and DIC... I feel like I'm running circles with this car. If anyone can repair Saabs , they can fix anything.