I have a 98 ram with the 5.2 eng. it will run rough most on cold start or after it has sat for about 1/2 hour. if you hit the gas a few times it will clear up.it has low vacuum when this happens. full tune up done, iac replaced, map sensor replaced, throttle body cleaned and it has not changed.

SOURCE: 1998 ram 1500 5.9 gas rough idle,hissing sound from air filter

SHOWING MISFIRES ON SCAN TOOL?IF NOT,ENGINE CONTROLLER HAS NOT LEARNED MISFIRE MONITOR..WILL HAVE TO BE DRIVEN A BIT FOR RELEARN..IF YOU CAN SEE MISFIRES..MISFIRING ON MORE THAN 1 OR ALL CYLINDERS?CHECK UNDERSIDE OF IGNITION COIL FOR CRACKS..IF NOT CRACKED,YOU MAY HAVE A FAULTY CRANK SENSOR..ANY CORRODED PLUG WIRES AT DISTRIBUTOR CAP?ALSO CHECK IF ANY OIL PRESENT IN INTAKE MANIFOLD..GASKET ON BOTTOM OF INTAKE MAY BE BROKEN CAUSING AN INTERNAL VACUUM LEAK

SOURCE: 1996 Dodge Ram 1500 4x4 5.2L engine. Truck stalls

idle air controll motor is bad

Marvin

• 85242 Answers
• Posted on Dec 05, 2012

SOURCE: i have a 98 ram with the 5.2 eng. it will run rough most on cold start or after it has sat for about 1/2 hour. if you hit the gas a few times it will clear up.it has low vacuum when this happens. full

Hello
When the service engine soon light a yellow light (Also called the check engine light or engine management light) is turned on this is to alert you to the fact that Powertrain Control Module (computer) has detected a failure somewhere in the systems it controls you may not feel any difference in the way the engine runs, this can be the transmission or the engine or emission system, there are fault codes set in the modules memory for these faults. What needs to happen now is to have the powertrain control module scanned with a special tool called an OBD2 electronic engine control scanner or a OBD2 code reader. Once the code(s) are read then you must perform the diagnostics for each code and make the appropriate repairs based on the findings of the diagnosis that was performed, this is called doing "Pinpoint" testing.