Hey Guys:

The last 3 mornings, I have had a weird issue I cannot diagnose. When I get in my truck (cold in the morning) and I start my truck idles and runs just fine. When I go in reverse or in drive, my rpm's drop to about 350 and it feels like it will die (but it does not). If I hit the gas its fine, rpms go right up. Then a few miles I will drive, the next stop sign, come to a stop exact same thing (low rpms, feels like it will die at a stop, during this time if you put it in park, the rpms go up to 600 and its fine, go back in drive back down they go). After about 3-5 minutes my truck starts to warm up and it goes away. So it seems to only happen in the morning, when I come out after work, it runs just fine again.

This used to happen intermittenly to me, maybe every couple weeks, but now since it got a little colder here, it has done it 3 days in a row.

NO SES Light
Just did my LIM gasket on monday, went really smooth.
New cap, plugs, wires, 10K ago.
Fuel Pressure is good.

Is there anything else that I could be missing, just curious if its fuel or spark, any ideas fellas?

 

when you start your truck does it idle at about 1000-1500rpm? i kinda had the same thing going on last winter for about 4 days then over the next three or four days it would idle a little faster and faster each morning until it was back to normal. i just chalked it up to the computer doing different things with mixture and idle speed. because when the engine is cold the fuel mixture is richer and it idles faster (usually) to get the temp up. so i would say if it doesn't change in a week or if it gets worse then you might have a problem with the IAC (idle air control) that would be my first guess anyways. or maybe the sensor that increases the RPM for accessory use (like power steering) i completely blanked the name of it. you could test that sensor by turning your wheels at a stop and at idle and if it dies or drops rpm by a lot then there's a problem. but if it were me i would wait and see what happens over the next week.

 

Hey, thanks for your reply.

Yes when I start it and am still in park first thing in the AM, my rpms are up (not exactly sure what at exactly) but will check tomorrow morning. This is fine, I let it run for a 10-15 seconds, then throw it in reverse and they dip asap. Then in drive, they stay low, and when I get on the gas (obviously the go up). It is perfect after 3-5 minutes after the temp goes up slightly. I will be keeping an eye on it though, hopefully it just is temporary....