Contour Enthusiasts Group Archives Forums Modifications Duratec Performance rough idle with MSDS

I recently had MSDS headers installed on Friday. The car continues to idle quite low (below 500 rpm) during cold start-ups and will sporadically shoot up and down (between 1500 and 250 rpm) while it seems to "hunt" for proper idle. When the car reaches normal operating temperatures, it seems to idle fine, i.e. about 650 rpm, but will sometimes dip to 500 rpm and below. I just checked the installation and everything looks great with no obvious problems. I used new sensors and have other typical mods. to the engine and exhaust, but the car ran fine before installing the headers. No other problems are noted when driving other than at idle and there are no CELs. Any help would be appreciated.

Did you reset the PCM? I've got $5 on it.

Yes, sir. I disconnected the negative battery cable, re-attached, then let idle at 1500 rpm for approximately two minutes (according to Haynes).

What if the nut on the EGR line wasn't screwed on all the way (where it installs on the header)? Would that cause this problem? When viewing it, there are still several threads showing on the nipple. Is this normal for the installation?

I would be safe and pull the cable and both necessary fuses for about 15-20 min. If you pull the cable for 2 min. I don't think that resets it. IIRC if you pull the 2 fuses for 2 minutes it works. Was there a noticeable difference when you reset it? As in, did it start back up and idle abnormally high for an extraordinary amount of time?

When I drove the car home from the shop, it was idling very low and stalled once. When I pulled the battery cable to reset the computer, it seemed to improve initially, but problems are continuing to occur. I do believe it was idling high (around 1500 rpm) when I did this, but rpms did eventually drop. But to be sure, I will pull the cable right now for the about 20 minutes to see if it makes a difference.

The car is now idling at 750 rpm. Rpms rose briefly after I started the car, but gradually worked its way down to about 750 rpm within several minutes. I'm going to let the engine idle for awhile and let it reach normal operating temperatures before revving the engine to see if it will consistently return to normal idle. Will see, but maybe I owe you five bucks.

If not that make sure you aren't running lean somehow w/ the headers. Either from too much air, not enough fuel or [censored] plugs/wires.

The car consistently went back to proper idle (650 rpm) after revving the engine numerous times and after it had reached normal operating temperatures. I haven't started the car yet today to see how it will idle, however. I'll keep my fingers crossed. I'm using double-plat. Autolite plugs with Magnecor wires that were replaced this summer. I'm also using a KKM intake with a new filter. Unfortunately, I'm not comletely sure of the condition of my fuel system, but it is maintained accordingly.

Your fuel system should be okay then, but just keep it in the back of your mind. I'd strongly consider cleaning out your UIM and replacing your gaskets. Now is a great time with the increased air flow as it is, it could only help. I had a problem with my car having a rough idle, but it was more or less what I explained to you. We cleaned the UIM and made sure it had new gaskets and everything was plugged in, we cleaned the injectors and the fuel pump seemed to work fine. Finally I replaced the wires and thats all it was. I was getting a lean CEL code from a cyl. 4 misfire. The wires gave me another 5hp on the dyno. W/ the headers I'm just short of 180, which could easily be bumped over 180 if I ever finished my exhaust and got a new K&N.