> Engine runs rough.
> Replaced both Cylinder Head Gaskets …
Included Exhaust Manifolds Gaskets, Upper & Lower Intake Manifold Gaskets.
> Tested Cooling System Constant Control Relay Module (CCRM).
> Tested Engine Coolant Sensor.
> Replaced Valve Stem Seals. Umbrella type.
> Rebuilt Fuel Injectors.
> Cleaned, lapped, and reseated Valves.
> Replaced Spark Plugs.
> Replaced Spark Plug Wires.
> Cleaned small amount of oxides from distributor cap (inside) aluminum lugs.
> Distributor / distributor timing has not been disturbed. Distributor housing still set at OEM chisel marks.
> Replaced EGR Valve Control Solenoid. Was activating check engine light and chime. CEL now off.
> Cleaned internals on IAC - Idle Air Control Valve; no difference. Then also replaced IAC; no difference
With IAC connected engine idle is a little rough. Without IAC it is the same; rough, but have to adjust idle stop to keep engine running. Installed temporary slip blind at IAC but found no difference.
> Cleaned internals and tested diaphragm at EGR Valve. Remounted valve w/new gasket. Installed temporary slip blind between EGR and manifold; found no difference in idle quality. Pulled slip blind.
> Tested TPS – Throttle Position Sensor.
> Cleaned and tested MAF – Mass Airflow Sensor 3-times. Even disconnected with engine running and there is only a very slight difference in idle quality... Maybe gets a tiny bit worse.
(1) power circuit good. (12.34 V)
(2) ground circuit good. (12.69 V)
(3) 2nd ground circuit good. (12.69 V)
(4) * MAF electrical “signal” swings a few hundredths of a volt along with engine roughness swing at idle
= approx 0.78 to 0.810 V. Voltage numbers rise and fall fairly smoothly during rev up to 1500 rpm and coast down.
> * When engine rpm is increased (by hand) it will not hold at a steady rpm.
> Idle rpm 510 to 520. Spec calls for 550.
> Have not tested O2 sensor.
> Soaked every imaginable vacuum hose, fitting, component, with carb cleaner; no change in idle.
> Engine vacuum at upper intake manifold 18 to 18.75 in. At idle. Needle bounces within the range.
> Now have trouble codes 56, 35, 63.
> Tired of throwing money at this car / money pit.
> Car only has 45,000 total miles.
Monday, April 2nd, 2012 AT 2:28 PM