Second mile syndrome

Maintenance/Repairs
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1

My Chrysler has suffered from a “second mile syndrome” for several years that comes and goes. Right now it has been doing it for about 6 months.

When I start the car in the morning it runs fine.

When I start it again later in the day after work to go home, it will go fine for the first mile. For the second mile it will kick, sputter and try to stall. After the second mile it will run fine for as long as you go.

I believe the problem has to do with the engine temperature and sensors that change the gas to air ratio. It seems to happen just when the temperature touches the “normal” range.

My mechanic that has been repairing my cars for years is stumped. Thru the years, he has replaced the computer brain twice, every sensor he can find, the electronic distributor, thermostat, etc. with no success.

All articles with stalling seem to deal with the problem happening all the time. That does not apply to my problem during the “second mile.”

Any help?

2

@computers

Has your mechanic tested the engine coolant temperature sensor?

Perhaps it’s no longer accurate

FYI . . . replacing the engine control module is extremely expensive and should ONLY be done when ALL other possibilities have been conclusively eliminated. Without a shadow of a doubt.

Far too many modules get needlessly replaced.

3

My mechanic has replaced all known sensors that relate to temperature including the ECT. Thanks anyway!

If the problem happened all the time it would be easier to fix but it only is during that “second mile.”

4

Chrysler New Yorker? Distributor? How old is this car?

5

There’s a variety of problems that could cause this. A sticky EGR, problematic PCV, crank sensor, ignition coil, MAF/MAP sensor, O2 sensor, ECM-coolant temp sensor, vacuum leaks, etc. Unless your mechanic has access to the Chrysler scan tool, hold on to your wallet, this may require a trip the Chrysler dealership.

I guess it is worth trying a few other things first. hmmm … just thinking … ok, the fact that it runs fine in mile 3, after going through the second mile problem, that to me seems like it unlikely to be a faulty temp sensor. More likely to be one of the others, or a faulty ECM itself.

One question: Is the check engine light on, or does it come on, then go off while driving?

The reason I say this, sometimes the engine computer runs the car in open-loop mode at first, say for the first mile , where it isn’t checking the sensors, then it starts checking, and adjusts the fuel correspondingly, going into closed loop mode. It may be that when it goes into closed loop mode, the ECM finds it cannot make the car run correctly, so after a mile it goes back into open loop. But if that were happening, the check engine light I expect would be coming on.

If the CEL isn’t turning on, be sure that it at least lights up as you start the car, when the ignition is in “on” but the engine isn’t running.

Also, try various controls when this happens. If the AC is on, turn it off. If the AC is off, turn it on. Note the difference. Likewise with the xmission. If it happens in 3rd gear, try 2nd, or 4th. When it happens, then if you briefly stomp on the gas, does it make any difference? Try different speeds, from parked at idle, up to freeway speeds. Any difference?

6

There are scanners that record data as you drive.
Might show just what’s going on.
I wonder if there is a shop that would loan one out.
I have one of these, works with a laptop.

7

The check engine light does work but does not come on for this problem.

When I mentioned “distributor” I was referring to the computerized version on my 91 Chrysler.

As much as I don’t want to go the extra expense, I might just have to go to a Chrysler dealer. They charge excessive rates.

8

Any gas engine needs a richer mixture when it is started “cold”. As the motor warms up the mixture (ratio of gas to air) needs to lean out to what the motor needs when warmed up. In the old days a choke did this and the amount of choke was controlled by the driver. Since driver’s are clueless an automatic choke was devised. Now cars with fuel injection are controlled via a computer that relies on information provided by sensors to change the fuel/air mixture as needed.

I will assume this is a recent Chrysler with a fuel injected motor. If in fact it is a vintage Chrysler with a carb then the choke needs adjusting. Back to a FI motor. When your motor is restarted it is “semi - warm” but the sensors and computer are reading that it as a cold motor (such as the 1st start in the am after sitting overnight). This is either a sensor issue, a bad PCM (central computer) or a PCM that needs to be reprogrammed (or flashed). Since Chrysler dealers have more specific and sophisticated computer flashing and diagnostics, the OP should not be going to a general mechanic at this point. A trip to a Chrysler dealer is the way to go.