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1997 Escort idles rough or dies

My 1997 Escort Wagon (manual trans, 170K) has recently started to idle rough whenever it comes to a stop, though never when the engine is first started. Sometimes it is a rough idle and sometimes it actually dies. It has also died when coasting to a stop.

I have replaced plugs, plug wires, and fuel filter, without improvement. Is it necessary to retrain the computer by disconnecting the battery? Could there be another cause I have overlooked?

If you have not done it yet, clean the throttle body with emphasis on the Idle Air Control valve and passages.

First, is the check engine light on? If so have the codes read and post them back up here (the actual codes such as P0123 - not what anyone says about them).

Second, you didn’t mention the air filter in the above - has that been checked/replaced? When you pull it go ahead and clean the MAF sensor.

Third, I would check for vacuum leaks. You can start with a visual inspection and then move on to listening around all vacuum hoses for hissing - you can use a piece of hose like a stethoscope.

Researcher’s advice is also good - make sure you use something designed for throttle bodies as there is a protective coating and those are designed to not take it off. The idle air control valve is pretty easy to pull off and clean on that so I’d suggest pulling it completely. You will want to have a new gasket handy for it.

The test to see if the problem is the IAC valve is to see if the problem goes away with a tiny bit of throttle opening.

Yes, the check engine light had been lit for some time (long before the rough idle was a problem) prior to disconnecting the battery. It is off now, but as soon as it comes back on I will get a code for it.

The air filter looked to be OK. I have a spare filter, so I may replace the air filter and see if it makes any difference. How do you recommend cleaning the MAF sensor? Compressed air? Solvent? Thanks.

I did notice a hose that was disconnected, and although I did reconnect it, I think it might still be leaking as the end of it is split. It is hard to tell if the other end is split, as it attaches in a very hard-to-reach/see place. I’ll tackle it again this morning.

Where is the IAC located? My Haynes Repair Manual is not helpful in locating electronics. When you say “throttle opening” I presume you mean increasing the RPM by increasing the fuel flow, correct? Thank you.

To clean the MAF get a can of MAF Sensor cleaner from and auto parts store.

Figure out the hose and replace it even if that isn’t today’s problem - things like that are usually pretty cheap.

The IAC controls air flow at idle. If it is stuck closed, opening the throttle a little would smooth things out b/c it would let air pass - so it increases air flow. To find the IAC just follow the big black intake tube from the air filter toward the engine. It attaches to the throttle body at the end opposite the air filter, and the IAC is bolted to the top of the throttle body (2 bolts, I think 8mm).

OK, many thanks for the tips. The hose is replaced (89 cents), and the MAF Sensor has been cleaned. It did not look at all dirty, but I followed the instructions on the can and gave it 10 short blasts of the cleaner. Hope that is the right method.

I see the IAC. What sort of cleaning is appropriate? Soft rag? Compressed air? Solvent? I would hate to mess it up, as this seems to be an expensive part ($90). Will the gasket still be useable if I remove the IAC?

I did disconnect/reconnect the battery and drove a few miles. The rough idle has disappeared, but there is a slight variation in the idle speed, according to what I hear. It alternates, slightly faster, then slower. Maybe this will smooth out after the computer relearns the current parameters.

Did you ever get the codes read? That would be good to know.

To clean the IAC just use a throttle body cleaner. Blast it in there, let it soak some, blast it some more, etc.

I would not count on the old gasket. Find a new one (cheap) or you can cut one out of karropak gasket making sheets.

While you have it off clean the electrical connections with some of the MAF cleaner (which is basically electronics cleaner). I also like to make sure the rubber seal on the plug is nice and clean & I hit it with some dialectric grease.

Variation is idle speed is often associated with vacuum leaks. You might actually check that first. Cleaning the IAC isn’t a bad idea but you might not need to.

The car has lasted longer than it was designed to last. I recommend that you start looking for a car.

I have not touched the IAC yet, but after driving the requisite miles, the idle pulsates, rather than being a steady RPM. I did read the code, which is P1443. What does this indicate?

If the Escort had qualified for the clunkers program, I might have considered a new vehicle. Still getting over 30 MPG, the body is in great shape, and the seats are comfortable. I just replaced an original headlamp! I will drive this one into the ground unless Uncle Sam buys me out. US manufacturers do make some decent vehicles - oops, this Escort was made in Mexico.

The P1443 code is for the evaporative emissions system (captures gas fumes from the fuel system & sends them to the engine to burn). It indicates a potential problem with the purge valve or solenoid - the parts that actually send the fumes into the intake. The problem is apparently pretty common on these cars. First you should find your evap hoses - look for a small black vacuum line coming up near the firewall in the vicinity of the EGR valve. You’ll have to look sort of deep behind the engine since it does run underneath the battery. It will go to your evaporation canister down underneath the airbox - hard to see - its sort of buried in the front fender area. Another hose from the evap canister will run to the purge valve & solenoid. Check all of those hoses for breaks or blockage.

If you pick up a Haynes or Chiltons manual it should give you specs for testing the valve & solenoid. You can replace both for about $50.

Of course, this is not likely to cause a problem with your idle. So maybe you’ll want to sort that out first.

If you haven’t yet then you want to check for vacuum leaks. If you have a vacuum gauge just use it (if you have one you’ll know how). Or you can take a piece of hose and use it as a sort of stethoscope - go all over any vacuum connections you see and all over the intake manifold - listen for hissing. Alternatively, if you have a propane torch attach a hose to the end, turn on the fuel but DON’T light it, and feed propane all around those areas. If you hit a leak the engine will respond. Don’t miss the vacuum line underneath the throttle body - thats where the evap system feeds in the fumes, though if a leak was there I don’t think the computer would “see” it to set that code.

If you don’t find any leaks I’d clean the IAC.

Once the deluge passed, yesterday I was able to track down a leak in the hose that runs from the PCV valve. With that short piece replaced, the idle is now very steady, not pulsing or throbbing at all. Thank you for alerting me to seek out the leak.

I cleared the P1443 code, and will drive for a few days to see if it reappears, before attempting to fiddle with the purge valve and solenoid. Hopefully replacing the hose will be all that was needed.

OK, the SERVICE ENGINE light returned, so I located the Purge Solenoid (E5TF-9C915-AA) which looks like a metal cylinder, and the Evap Purge Sensor (F57E14A606-BA). The exterior of the hoses were not in great shape, but I did not detect any leakage. I’m not sure how to test either of these, and my Haynes manual gives no clue at all. I tried blowing through the solenoid, and no air would pass through in either direction, so maybe this is the problem. Air passed through the Sensor readily when I blew into it. Are there definitive tests for either of these?

My Ford parts department sells a kit (F7CZ9C987AC) to replace both of these, but they want $169 for it. An online store offering Ford parts sells it for $100. That might be the best alternative, but still a far cry from the $50 you estimated. What do you think?