Contour Enthusiasts Group Archives Forums Modifications Zetec Performance Mystery Problem!! Please give your 2 cents!

My car has been doing some really annoying stuff lately, which I have yet to make much sense of.

The idle has been erratic, ranging anywhere from as low as 250 rpm to as high as 2K.

The CEL pops on and off periodically, and the power will surge, sometimes giving a sudden spike in power, making the car jump uncomfortably, and sometimes will bog down as if it will stall out.

All these symptoms are intermittent, only lasting for a second at the most. I hooked it up to the scanner, which gave me a code 57, which I believe is EGR related, but that doesn't make sense because the power only surges while accelerating. I thought one of the cylinders might be missing, so I checked the plugs, which were fine, and reset the ECU.

On a first look though I noticed the oil cap had come loose and a bunch of oil had blown through the opening and splattered over the valve cover. After a lot more useless troubleshooting I also found the PCV hose from the valve cover had come loose at the airbox vent. I think the problem may be related to a build up in crankcase pressure, but I can't figure out why or why it would cause these symptoms. I can still drive the car, it runs and at most the problem is just plain annoying, but I want to address it before it gets worse and causes damage.

Any personal experience or insight would be greatly appreciated, I'm sure similar problems have been addressed before but they're somewhat hard to locate in the millions of current and archived Zetec Maintainance posts.

I had the same problem on my old 91 Chevy S10 Atx. It either idles real low to the point of stalling or it goes real high to you think its going to put a piston through the hood. Check you transmission fluid!!! Apparently I had a ever so slow radiator leak where the tranny fluid goes in and i was wicked low on tranny fluid. The engine surges cause it senses that its low on fluid and to keep it lubricated it surges to speed up the amount of fluid thru the system back to the tranny itself. If your tranny fluid is fine, then the pvc hose that went to your air box might have been the problem. Irregular air flow will cause the engine to do some weird things. I'm assuming that you replaced the oil that you lost right?

If none of that works I would say do a complete tune up on the engine. Check your plug wires, plugs, air filter, oil filter, new oil, also check your fuel pump.

If its not any of that I have no idea man.

~Dan

Well, I had a bad intake manifold gasket which caused a horrible idle but no spike in power.

Give it a complete tune up. Replace the plugs, wires, dump in some injector cleaner, and clean the MAF. Old plug wires can develop microscopic cracks that let them arc to ground.

Have you replaced your PCV? I did mine at 80k and it was insanely clogged up. Yours may be sticking shut causing the problem. You are building up pressure in the crankcase causing it to bog and then it is suddenly released.

You can also check to see if you have a vacuum leak be spraying carb cleaner around the areas that you think you may have a leak. If the carb cleaner gets sucked in by the vacuum leak, you idle will jump up for a second.

HTH,
BP