'03 5.4screw-first startup after long period cooldown, I watch my RPM's at startsup and they go up to 1100 (normal), if I put it in "D" right off the RPM's go UP 300 BEFORE going into gear. The truck them "jumps/surges" like, let's go! If I let it idle for 1-2 minutes and the RPM's drop down say, 200 it does not "jump".
It's getting colder in MN, and it seems to take longer (of course) for RPM to slow down a bit.
Any thoughts? Normal?
Anyone that can confirm that I'm not crazy by watching their RPM gauge in AM startup I would greatly appriciate it!
Love the truck otherwise!
Jeff in MN

 

truck just wants to go

but I dont really know what could be causing that, in winter I let my engine warm up and rev it like every 30 seconds and its around 800rpms a couple minutes later.

 

Any thoughts?

 

Mine does the same thing. I think that's pretty normal.

On startup (especially when it's colder) the truck idles a good bit higher because it is running richer and trying to warm itself up before it slows to its normal idle speed. So that's why it idles higher.

I have noticed in mine (again especially when it is cold outside) that immediately after I put the shifter into D the RPMs jump up a couple hundred until the tranny gets into gear and liek you said, the truck feels like it's going to take off. I think this is just the engine computer adding a little throttle so keep the engine from sputtering when the load of the transmission is applied. The engine just needs a little more gas to keep itself running smoothly until it warms up. That'd be my explanation, may not be exactly right, but that's my impression.--DIY

 

Yeah, I've seen this topic discussed here before... pretty recently. Just do some searching and you'll find a thread with pretty good explanation of what's happening. But DIYMechanic is basically right... you're truck is doing what it was programmed to do... the same thing my '06 does... warming the engine from a cold start. Let it sit for 30-60 seconds after starting and the RPM's should drop down to a normal idle and you can safely put it into gear without the surge.

 

Thanks for the replies, I will have to slow down when leaving.
I'm glad to have backup to the questions we all ask on this forum.
Will search for "mechanics" of the warm up.
I'm just used to all of the aother cars/trucks that I've owned not jumping like that when dropped into gear.
Thanks for all the feed back. this site ROCKS!

 

There is a cold start stratigy in program that when the PCM detects quite low ambient temps from the ECT and the IAT, the fuel table is set to a very rich condition.
At the same time the IAC is opened up for more air AND a timer kicks in until there is enough heat in the engine and the timer runs down.
After the oxygen sensors heat up and begin takeing over fuel control, the idle speed comes down to normal.
That is what you see happening in low temps.
This has been cold start stratigy since 1985 FI and even before that with carburation and automatic chokes..
If it didn't work this way you would complain of stalling and no cold drive-away.