View Full Version : '94 SC Rough Idle Problems

06-14-2005, 12:03 AM
I am having rough idle issues with my SC that have been occurring for about 2 years. I recently went about trying to resolve them and have performed the following:

Had fuel injection cleaning service performed.
Replaced IAC valve (after attempting to clean it and having the diaphragm split).
Replaced worn engine and transmission mounts with OEM mounts.
Replaced the CAM position sensor (for the second time in 18 months) because code 214, Cylinder identification circuit fault, was occurring again.
Replaced the spark plugs and wires with Motorcraft replacement parts (with the new replacement plug since the double platinum are NLA - at least not readily).
Installed the teflon gaskets in the I/C tubes.
Replaced a bad vacuum line that had disintegrated (I believe it lead from a vacuum rail near the EGR valve, behind the throttle body, to a vacuum rail that runs down the passenger-side strut tower and forward along the frame rail past the radiator to what I suspect is the canister purge solenoid.

After completing the plugs, wires, I/C tube gaskets, and repairing the vacuum line this past weekend, I went through what I found documented as an "Idle relearn" procedure this morning and still don't see a noticeable difference in idle quality. I have noticed that I have not yet had a complete stall, which I was having on a fairly frequent basis before. While waiting on the engine to warm up for the Idle relearn I noticed the stock vacuum gauge was reading a steady 20 in Hg in Park. After starting the relearn, under load in Reverse/Drive, it read around 17 in Hg. After driving it today, it now reads 17-18 in Hg in Park/Neutral, with RPMs around 700-715. In Reverse/Drive witht the brake applied, RPMs initially dip to the 450-475 range and then recover to about 500-525. The vehicle did pass an emissions test this morning after the idel relearn and 10-15 minutes of driving. No codes are being called out at present during the KOEO test. There also were none present prior to clearing them for the Idle relearn. The last KOEO code was 214 prior to the most recent replacement of the CAM position sensor.

I don't know if it means anything, but I also replaced the radiator about 9 months ago and while I was refilling it, I had started the engine with the radiator cap off (as the Haynes manual indicates) and the engine stalled, pushing coolant back out the radiator opening. I don't know if this is a normal occurrence with the engine still cold.