Running Rough at idle and loss of power with hesitation
I have read alot on this forum regarding my problem of rough at idle and loss of power with hesitation with my 1994 Pontiac Bonneville. The specifications for my vehicle are:
Body style: 4-door sedan
Layout: FF layout
3.8L Series 1 L27 V6
Years Used: 1992-1994
•Family: GM 90° V6
•Model: Series 1 3800
•Displacement: 3,791 cc (231 cu in)
•Stroke: 3.40 in (86 mm)
•Bore: 3.80 in (97 mm)
•Power: 170 hp (127 kW) @ 4800 RPM
•Torque: 225 lb·ft (305 N·m) @ 3200 RPM
•Fuel Type: Gasoline
•Aspiration: Normal - Non-Supercharged
Transmission: 1992-97: 4-speed 4T60-E automatic
Wheelbase: 110.8 in (2814 mm)
Length: 1992-95 SSE: 201.1 in (5108 mm)
Width: 1992-97: 74.5 in (1892 mm)
Height: 55.7 in (1415 mm)
1998-99 SSE: 56.0 in (1422 mm)
Fuel Capacity: 18 U.*. Gal
I checked the coil packs and the spark plugs, the fuel injection, as well as there were no error codes to be had. I also checked all the sensors and computer(*). I even checked the coil packs and spark plugs the "Old Fashioned" way, (pulling a plug wire off the coil pack one at a time while the engine is running), and discovered that even though there was spark and fuel to all cylinders the number 5 cylinder was missing badly and it didn't matter whether or not the spark plug was connected and firing or not.
Then I learned that this engine series has a habbit of burning exhaust valves. The only way to determine this is to perform a cylinder compression check. If there is 1 or more cylinders with low compression, then you can just about bet it is a burned valve.
The tollerance for the compression check between each cylinder is:
100lbs No more than a 70% variance of the highest to lowest readings.
I also learned that you have to replace all the cylinder head bolt each time you remove them since they are "Expansion" bolts.
I hope this helps wth whoever may be having the same issue and has been throught the gambit as I have.
Thanks for all of your advice as well as your different ideas and checklists of things to go over.
Last edited by mhoflin; 01-22-2009 at 12:28 AM.
Reason: Model Reference error and grammar errors