Cadillac: High RPM and Rough Idle Problems, mass flow sensor, mass air flow sensor

Question
Still have RPM problems and rough idle.  I Am presently using Snap-On Vantage Pro (expensive computer!!!) to check the engine and it has come up with the 6 and 7 cylinder problem.  Swapped the coils (found nothing), swapped the ignition module (found nothing), swapped the plug wires and spark plugs (found nothing).  Checked-cleaned the EGR and Mass Air Flow Sensor (throttle plate) and both were working properly.  Idle speed control is good.  
Tomorrow plan on cleaning injectors (6-7) and swapping out the O2 sensor.
This car is tough!!!
Any additional ideas would be appreciated.
Thanks!
Dave

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, August 03, 2006 7:21 PM
Subject: AllExperts Reply to your question


>
> Hello! An answer to your question:
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> Followup To
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> Question -
> Checked the ISC and mass flow sensor and they seem to work properly on my 94 Cadillac Eldorado, engine:4.6L / 279 CID / 8 cyl / Gas /
> DOHC  Fuel: Fuel Injection / multi port  Ignition: Distributorless  Trans:  4-speed Automatic Transaxle (Electronic)  Mileage: 134,000 miles  Emissions: obd1  Misc Data: 2 dr coupe  Symptoms: Poor Idle Quality  Occurs: ColdStart Idle  More Info: Can the ICM cause a fault in one coil and not effect the  rest?  TEST AND REPAIR DATA COMPUTER CODES AND DESCRIPTIONS: PO135 ISC malfunction    TESTING AND RESULTS:   Fuel pressure: good    RELATED REPAIR HISTORY:    Car still has rough cold start up, found and fixed fuel regulator it was leaking and loading up with fuel. Would run rough if sitting  for a while, then clears up
> and runs smoothly. Now I have found number 6 and 7 cylinder not  firing good. Scoped all
> cyls, found 6 and 7 with very low readings on scope. Swapped with coil next to it, and no  
> difference. Plugs are good. injecters not leaking. This one's tough!
> Dave Williams   
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> Answer -
> Did you fix the P0135 code and then CLEAR the codes and rechecked diagnostic codes to see if it or another code appeared ?.
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> tom
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> Cleared the code and rechecked diagnostics--no other code appeared.  Think I might have to do this, because cylinder 6/7 are weak, I am going to replace the control module (not the coils)to see if the module is not the problem.  
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> Dave
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Answer
What I use to detect a faulty injector is a temperature probe right next to the injector at the cylinder to see what temp it is running. If it is running HOTTER than the other known good cylinders this would tell me that it is an injector. If it is colder it could be ignition to the sprak plug which I would verify FIRST and then suspect the injector.

tom