Running rough and shutting off after replacing the radiator?

1TOMMY

MEMBER
1999 JEEP GRAND CHEROKEE
4.0L
6 CYL
4WD
AUTOMATIC
2,000,000 MILES

The radiator busted going down the highway and it overheated. Changed the radiator. Now the vehicle won't stay running at idle seems to run fine once you get it up to speed, but once you slow down it shuts off. No sign of a blown head gasket or crack block. It does have a strong smell of gas like its flooding. What could be the other possible causes for this?

1 Reply

CARADIODOC

MECHANIC
33,752 POSTS

Did you disconnect the battery when you replaced the radiator? If so, the Engine Computer lost its memory. Sensor data and fuel trim numbers will be relearned as soon as you start driving, without you even noticing. The one notable exception is "minimum throttle". Until that is relearned, idle speed will be too low. You may need to hold the accelerator pedal down 1/4" to get the engine to start. You won't get the nice "idle flare-up" to 1500 rpm at start-up, and it will tend to stall at stop signs.

To meet the conditions for the minimum throttle relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.

Let me know when you've done that and if it solves the problem. Here's links to some related articles that might be of interest:

https://www.2carpros.com/articles/engine-stalls-idles-too-high-low-after-dead-or-replaced-battery

https://www.2carpros.com/articles/stall-at-idle