Ram 1500 running lean need rich advice

BILLDOUGY

MEMBER
DODGE RAM

I have a 98 Dodge Ram 1500 318 4x4 with 7000 miles on the new motor that after running through water runs lean. I have checked and there is no water in the oil/oil in the water. At cold idle it runs like a champ. Once the truck warms up I have the problem of it running way too lean and the truck wants to die out. Once it warms up it starts missing out at idle very bad. It does not have much of a problem as long as I am giving it at least a little gas. As soon as I let off the gas even when under no load it will drop down to about 300 rpms and try to die. Most of the time it will pick back up but there is always a miss at operating temp. When I go to stop is when I have the issues. I I do not think it is the fuel filter since it runs fine at idle and it will rev just fine cold under a load. I have probed the Throttle Position sensor and it is within normal limits. Any suggestions would be very much appreciated.

2 Replies

DPWD23

MECHANIC
136 POSTS

You made a good start by checking the TPS sensor.
You will need to also check the following:
Mass air flow sensor
MAP sensor
Intake air temp sensor
Check fuel pressure at the rail
Check or replace the oxygen sensor.
Also check for a clogged EGR valve.

Check to make sure your knock sensor, oil pressure sensor, and temp sensors are all wired correctly and no shorts to ground.

Systems on these trucks run in "open loop" mode until they report optimal temp range. This is why it runs fine until it gets warm. When it gets warm, it starts using information from the sensors to make adjustments to fuel mix, timing, injector timing, etc.