Contour Enthusiasts Group Archives Forums General Troubleshooting Intemittant CEL on a '95 SE, at cruise

I just had my '95 SE, MTX out today for an extended hwy trip (~150 mi). Air temp ~85 deg. F.

While under speed control and tooling along at ~65-70 MPH, I kept getting a CEL that would turn on for 15-30 sec, turn off for several minutes, then repeat, no real regularity to it. If I let up on the gas, it would disappear almost immediately, then start over again shortly after I returned to cruise. It also goes away under medium to hvy acceleration. The CEL came on whether the A/C was on or not. The problem stopped after I got off the interstate and drove an additional 15 mi in normal local traffic.

When I got home, I immediately pulled the DTCs (OBD-I) and all the KOEO and KOER codes came up "111" - system OK.

I cleaned the UIM/LIM a few weeks ago and cleaned & checked the EGR passage in the UIM plus the EGR tube and valve and they all looked clean & open. Used new gaskets all the way around. The car has been running really well since the cleanup - I got ~27 MPG on the trip, pretty much what I used to get when it was brand new. The only thing I noticed was that when the CEL came on, the car seemed to, just barely perceptibly, bog and surge.

The O2 sensors are still the originals but I only have ~46K mi on the car. The pre-cats/manifolds were changed under the recall about 3 years ago.

Anybody got an idea where this gremlin is hiding? I'm sure at a loss.

Kurt

You can get a code reading at Autozone. The computer will remember the code, even if the CEL is off. Most common problem with the V6 Duratec is clogged EGR ports.Not a bad EGR valve, but the ports between the throttle body and the upper manifold are full of carbon. Not a bad job to fix, but verify with a fault code that is "EGR not opening" first. Take off air cleaner and throttle body, clean ports with a stiff wire or small screwdriver, vacuum out pieces. If the gasket is ruined between the throttle body and manifold, you will have to replace it. Order or get the gasket from a dealer, nobody stocks it.
Other common problem that causes an intermittent CEL is a bad oxygen sensor. There is two on the 95, one on each manifold. Good Luck.

Alkraut:

I pulled the codes myself, all were OK -- KOEO, continuous memory and KOER. The UIM is sparkly clean, EGR passage included as well as the inside of the EGR itself and the tube that connects it to the exh system (rechecked them all this AM). I've had the UIM EGR passage problem before, so I've seen those codes and know what the UIM passage can look like. The killer here is that the PCM is saying that everything is hunky-dory.

I would think that if it were one, or both, of the O2 sensors, that would show up in the continuous memory DTCs or in the KOER tests - nada.

Kurt