Contour Enthusiasts Group Archives Forums Modifications Zetec Maintenance Mechanic's Suggestion for Stalling/Rough Idle

well i dont know for sure but that would be the first thing i would look at. unmetered air flowing past the maf would cause all kinds of weird idle problems, from too low idle to too high idle to stalling out. i would suggest thouroughly inspecting all the vacuum hoses, for cracks, pinches, kinks and holes before replacing the tps (for the third time, which i find hard to fathom). i had all sorts of wierd idle problems after i had my engine replaced, come to find out the idiot mechanic left a hose disconnected off the EGR.

If the TPS is bad, you can probably detect that with a voltmeter, and it may well be possible to restore it with the same sorts of nonresidue cleaners that are useful for MAF cleaning.

Let me ask u this:

When u start the car, are u turning the key from the off position to the start position right away? Or, do u turn the key to On, let the fuel pump pressurize, and let the sensors "warm up", before starting?

The reason I ask is because this little detail is the difference between nice smooth running after starting, and the EXACT symptoms u describe in my GF's 96 Zetec Tour. Although the problem with her car won't happen every time.. theres been instances where I've gotten in the car, started it up forgetting to do the key trick, and had it start stumbling and missing/trying to die on me. The times this has happened I've killed the engine right away before the computer could throw a CEL, then turned the key to ON, let it sit for a few seconds, then moved the key to START and had it run perfectly, just seconds after it ran like total crap!!

I have cleaned this cars MAF sensor which seemed to help tremendously (this also singlehandedly took care of a pinging issue the car had).

My theory is all our MAF sensors are dirty and less accurate as the mileage gets up there... ESPECIALLY if you've added an aftermarket intake with an oiled filter.. these are known for gucking up MAF sensor filaments. I think the MAF sensor works by heating up one or both of those wires. The air coming in does something with the resistance in the wires and the computer can tell how much air is coming in. You can imagine if this part is dirty or just too worn out, its going to cause problems. The reason you're getting a CEL is because the engine runs like crap for a little bit and trips the lean code.

If I were u, I would disconnect the battery, clean the MAF sensor carefully, re-install the MAF, connect the battery, see if it's improved.. if not, do the key trick that I mentioned before.

Good luck!

Yeah you guys were exactly right. A few days ago, I cleaned the MAF with alcohol and Q-Tips, and put the MAF back in. Additionally I took out out the new TPS and put back in the old one the mechanic said to replace. CEL went off on its own, car is running great. So the clogged-up MAF was making the computer return a CEL of Low Voltage/Input on TPS. Turns out the NEW TPS I got from Autozone is broken, its got no resistance (the spring in it). So my whole problem has just been solved by cleaning the MAF. Thanks for all the help guys.

Hi guys- Just inherited (yesterday)from my Dad a '95 LX - 2.0L DOHC engine with 54K miles(very clean Florida car). Joined yesterday and already know how to fix clock, turn-on and improve fog lights, and fix passenger front window.
Read this post because engine vibrates badly in-gear at a stop; tach reads a steady RPM though. Any thoughts? Found paperwork in glove compartment saying "needs an engine mount". I took a quick look under the hood; there appears to be some top-mounts on pulley-side of engine. Must be some on the bottom too??

Yeah it has a good many of them, I'd assume the front and rear mounts under the engine take most of the weight and probably need replacing the most if it really does need it. I found that obtaining a smoother/quieter idle also helps. I did this with spark plug/wires change and switch to mobil1 oil.