I have an old Mercury Tracer that I drive to and fro work, Even if it is a '94 model, it looks and drives great for a car that has more than 100K miles on it.

Lately the engine will stop running when I am on idle. If I have to stop for a red light, I have to put it in neutral and rev up the engine so it will not die out on me. Except for this, the car is in very good condition. I just replaced the sparkplugs, wire set, airfilter, oil filter.

Do you guys know what might be causing this problem? Is there some sort of adjustment that I can do to "strengthen" the idle.

Any advise will surely be appreciated.

Thanks!

It sounds like you are not creating enough vacuum. You might want to check that and if there is a leak address that first.

You might want to check the blinker fluid.




Or, have it diagnosed.  Could be the idle speed
sensor, or the idle stop actuator (idle speed
solenoid).  The idle stop actuator is a little
round (usually) thingy about 1 1/2" in diameter
and about 7" long.  It has a plunger in it that
should activate when the ignition key is turned
"on", pushing the throttle to a partially open
position.  I'm just a shade-tree kinda guy when
it comes to this - I've rebuilt a few motors and
transmissions but this totally computer controlled stuff left me in the dust years back.

I'm only offering this advice because I had to
replace one on my daughter's 90 Escort.  It stuck in the extended position.  Idle speed:
3800 RPM's!!

a simple tune-up might help, or it will bring out the problems.

Gunslinger is probably on to something.  Did all
this start after your tune up????  It's very
possible that a vacuum line got knocked off
somewhere.

Another thing that's not very expensive to change is the fuel filter.  It might be dirty and not allowing enough fuel through at idle.

Definitely sounds like a vacuum leak. If you still have the vacuum hose routing diagram under the hood, use it to trace each line out and look for loose lines, broken fittings, etc. Roll the lines between your fingers to check for dry-rot, and don't forget to examine the larger line that goes to the brake booster, and the check valve (usually a plastic elbow) between the line and the booster, too.

Ditto on the Vacuum line and clogged gas filters.  I have had both.  Luckily both are cheap (and easy) to fix.  If the car has a removable air filter housing that you removed, many have a vacuum line(s) that connect to it and may have come loose.

I once had a brake booster that had a vacuum leak only when I applied the brake pedal.  The car would run rough and stall at stop lights/signs.  At a stop and idling, I could hear the RPMs changing as I pressed the brake pedal.  Pretty weird.

Running some injector cleaner through the gas could help if the injectors are clogged.

If you buy crappy gas from one location, try switching to another location.

The throttle body on my Escort GT (OK, not a hot rod, but its great on ga$ :p) every few years gets a build up gunk.  I use carb cleaner or throttle body cleaner to clear it up.

Those are the easy things.

Good Luck!

After 6 years, the OE battery in my pickup got toasted by the rough road to Telescope Peak.  One symptom of my extremely weak battery was that the car would not idle.  The alternator was clearly not up to the job of supplying all the electricity all by itself.  

Make sure your battery isn't ancient, and your connections are clean and bright.

I had this problem with my Mustang about 2 years ago.  It was the Idle Air Bypass Valve on my car.  You may want to check yours as well if so equipped.

I haven't had this problem, but I have read about it.  Cars (and trucks) with computers can act flaky if the ground on the battery is really corroded.  The ground voltage can float around and cause some very odd problems.

I'm convinced computers are good for surfing the web, but computers in cars?  Naahhhhhh.....

I would vote for a vac leak or the idle air control (IAC) valve.

check/replace your PCV valve. It should rattle freely when you remove it from the vehicle. If you haven't replaced it before, you are WAY overdue

Karl

The fuel injectors could be clogging.  A bottle of the stuff for $4-5 bucks would be worth a try.  Don't buy cheap stuff.... it don't work for big deposits.  I like OUTLAW brand.  especially applicable....YMMV

This is the great thing about this site!

We have a wealth of knowledge about almost everything.

Everybody who said vacuum got it right. After Gunslinger's reply, I immediately looked at it and viola! the hose has a leak. I took the most part of the morning looking for a replacement but could not find any so I just improvised  a high pressure/temp 3/8 air hose and replaced it.

While I was at it, I decided to replace the fuel filter too since Don mentioned it! You could not possibly just disregard 100 years of experience.  [:D]  [:D]  [:D]

Again, THANK YOU VERY MUCH GUYS!!!!!!