I have seen and read many posts in regards to the cold out side air temp affecting start up and idle. Any more help would be great. My 01 5.4 was having problems with idle below 48 F. I replaced the icv, cleaned the throttle body also mass air sensor and performed top end and fuel injector clean. It helped but did not fix. Also if i let the truck warm up with out putting on defroster it will get the idle surges. My guess is the condenser puts a load on the motor causing it to idle higher. Today was 26,truck didn't want to start it took two tries. then when it did start, even with the defrost on, was dieing out. I had to manually hold throttle at 2000 rpm until it warmed up. No check engine light. Again the work I have done has helped the problem significantly but not solved.

 

How many miles are on your 01?
What other things have you done as far as maintenance? Has the other basic maintenance been done, such as spark plugs, fuel filter, etc been done? How is the battery?

Just seeing where we are at.

 

176000. I bought it last February so the maintenance up till know im not sure. I change oil every 3000 or less. I know the that it has yellow top motor craft coil on. It didn't do it last spring when it was cold just started this two months ago. I am the third owner, the first owner had it until 2010 and she was an older gal that had all the routeing maintenance performed. it has new hoses and belts. I am not a mechanic but am mechanically inclined and would like to save my self big money by fixing it my self.

 

new battery as of July. It runs great! 21 mpg on highway does not burn or leak any oil.

 

well, i'm fired! seriously After gryffinwings asked how my battery was, I thought and thought some more...... I remember when I installed my aftermarket stereo I couldn't find a good location for my fuse block, due to the three inch tail off of the battery. So much to my embarrassment I decided that the plastic box between the battery and the fender well looked great. Ya, not so much. It is some sort of an air resivwour for the vaccume system. Hole patched! truck starts great again.. I'm a dork

 

Good learning experience . Glad you found out the issue and your truck runs great.

 

Sorry about not getting back to you, been pretty busy, yep, vacuum leaks or vacuum problems will do that.

I'm glad I was the instrument in getting your F150 running well again, congrats.

 

Well folks, replaced vacuum box, and also air temp sensor. My truck is still not fixed. I was sure that it was fixed. It started and warmed up good for two days after each part. Then back to the same symptoms. I called the steal-er ship. They have no clue without plugging it in. $128 for diagnostic. Any help fellas...... It doesn't do it right at start up. It takes about 30 sec to two minutes before it starts to bog down and idle roughly.

 

I would go buy a couple of cans of carb cleaner or brake cleaner. Cheaper of the 2. Spray the connections where the vacuum tubes connect. Around the the intake and gasket connections.
I had the gasket on the throttle body leak on the bottom. That was a bugger to find. I bought gasket material and made my own. When I was having code issues just changed the vacuum tubes. It's cheap, solved the issue.

 

I have pulled the throttle body and cleaned. No leaks on the gasket. I was thinking about buying new tubes but there is alot of em. The one that comes from the left of the brake booster and goes to the back/top of the intake rise down from the t/b is very checked and worn. probably should replace that first.