Need a little help with a problem from you guys
I used to post and be on here a while back, but haven't had many problems with the trucks and bought a D-max back in 2015. I put my 97 in storage and only use the 98 for hauling gravel and plowing snow in the winter months. The motor in the 98 only has about 22,000 miles on a rebuilt engine with new injectors. The problem I have been trying to defeat for a while is a poor idle condition during the winter months. It is there during the summer too, but not hardly noticeable. As the weather gets cooler, the motor runs erratic on idle. It chugs away like it has a big cam and runs really rich and loads up while varing it's speed a little . If anyone else asked me what could cause these problems, I'd say change the PCM. But done that, I have tried several different pump drivers ( none new, but none have this problem on another truck) and doesn't change the problem. I changed both the sensors on the intake manifold, I changed the heating element and the filter thinking for sure the heater was it. Notta. The electric transfer pump is building pressure too. Here's something strange, when it's running bad, if you unplug the manifold temp sensor, the motor straightens up for a few seconds before going back to rough idle. I question the accelerator pedal because it has the won't accelerate smooth and linear but I've tried 3 different ones and they all act the same. I can't remember how to check them with an OHM meter. I was debating a bad injector, but they only have 20K on them too. Still could be bad? Something changes as it gets colder.
What do you guys think??
97 2500 6.5, downpipe, exhaust, K&N #9 resis in PCM w/ cooler, B&M trans prog., 183,000 mi
98 3500 6.5, dually dump, downpipe, straight exhaust, K&N #9 resis in PCM w/ cooler, B&M trans prog, marine injectors, Western plow, engine rebuilt @231,000 mi
1993 GMC TopKick 50 boom trk w/ 3116 Cat
1968 Plymouth RoadRunner, built 383 auto
2005 Honda VTX 1800, with all the go fast goodies
1974 Plymouth Cuda , project yet
1994 Dodge Viper , 7000 miles
New truck payment "NOT IN THE PLANS"