Rough morning idle

Ok so after doing some looking around i found that the 99 3.4 doesnt have a cold start injector.So what could it be causing my problem? It only happens first thing in the morning, it will run rough and idle around 700rpm when it used to start and idle around 1800rpm. And being that its summer i would really like to fix this before winter hits. Has anyone had this problem? Or is there a cold start valve? Any help will be greatly appreciated.

 

Well, I can tell you what NOT to do. Mine was running pretty rough in the mornings (Mine would idle at 1600rpm), so I decided to run some seafoam through the vacuum line. It worked, but now I'm idling wayyyyy too low at start up and at stop lights (just above 500rpm). It's at the threshold where the truck will start vibrating if it idles for too long.

I would recommend cleaning the throttle body plate. That did absolute wonders for my fuel efficiency, maybe it would help with your start up.

 

I cleaned the throttle body when i did the MAF. But it was doing this prior to the cleaning.I was hoping that would have done the trickbut no go.

 

So you cleaned your MAF?

 

Try unplugging the battery for a while. I forget the amount of time required to clear the computer memory, but that significantly changed my idle once. Make sure to write down your trip distances (if it matters) before hand, because they will be cleared.

 

Yah i cleaned the MAF and had the battery unplugged while doing so. It idled high after cleaning it and is back to normal now. But the rough idle when starting started before i cleaned the MAF

 

I know my truck ran a little funny after I cleaned mine but if it was doing it before then

 

Check your idle control valve under the throttle body. I bet its got enough carbon in it to keep it from moving and or it has gone bad.

 

ok thanks! il give that a go!

 

Any chance you figured out your issue. I'm having really bad cold idling issues. When I start the truck it revs up for a few seconds then starts to kind of die down, spits a little, almost dies and then revs back up but it actually dies sometimes. It seems to be getting worse and dies more often but it's usually only when it's cold. My pickup is actually in the shop right now but this is the third time and they can't seem to find the problem. I've changed the fuel filter, spark plugs, cleaned the MAF, changed the PCV Valve and just recently replaced the throttle postion sensor because the mechanic told me that was the problem but it didn't fix it. They said they checked the ignition coil, plugs, rotor and cap, ect... Wondering if you figured yours out. Thanks