i have a 97 4.0 auto 4x4 and then ever its cold out side like under 40degrese out side the rpms will bounce from 500 to 1000 and some times die also wen slowing down like under ten mph the rpms will jump again and the whole truck will buck and at idle if it does it will go from l050 rpm to 1100 the whole time and the truck will rock a little. i don't know whats wrong with it if its warm outside itll drive just find but the weird part is if i turn on the heater and the compresses cut in it'll act a little bit better? i got no idea if anyone had this problem let me know so i can get it fixed . thank u

 

well with the top part you would think it to be a small vacuum leak. but if it runs fine in the warmer weather than thats not it. i would guess it still has something to do with intake being that it only acts up in the cold. try replacing IACV (idle air control valve) if the IACV isn't functioning properly it is likely to only notice bad symptoms when its cold out and the engine actually has to warm up. when its warm the engine is already at a temp where the influence from the IACV isn't all that noticeable. Thats probably your best bet... Good luck

 

thanks it ran great today because its 53 outside today but i sealed up a blown out manifold mesh gasket with jb weld and im leaving the bat unpluged allnight to wipe the ecu and hope that helps

 

Check your 02 heater fuse mine blew and caused it to run like crap at idle and die couldn't find the problem at first then after a couple weeks started belching black smoke replaced the fuse and was good to go. just a thought.

 

i will try that

 

well i could not find the fuse my manual said it was number 13 under the hood but the diagram in the manual wasnt the same as what i had but i checked every fuse under the hood but another thing it said the egr was on the same fuse and in most trucks u can feel the egr kicking it while in park and ive never noticed it in my truck im running out of options this is my work truck with out it im unemployed a

 

I just read the part about it bucking a little i wonder if your torque converter is not completely releasing the computer auto adjusts the idle for the load from the torque converter if its sticking on a little it may cause the erratic idle as well. Have you flushed the fluid recently? that may help it out. also if you flush it change the filter the oil passages may be getting plugged up with contaminants. it fits all your symptoms as the fluid heats up it thins some so that could allow it to slip passed the blockages if any seeming to correct he problem.

 

but it wont do it at all when its summer or nice so i know it cant be that its something electrical or vacume related im gettin tired of it

 

Maybe a bad weather seal in a sensor plug? condensation from the cold or rain may give it erratic signals? Just trying to narrow it down from the symptoms .

 

its just weird and my inlaw as a 94 with a 2.3 in it and its been doing the same thing but not deing all the time its a stick so it doesnt buck him so bad but i now kno its something that a 4 and 6 cyl both have but thats still a fucn lot of things to go threw and the colder its been getting the less and less power i have and it has a real rough idle when its a cold morning but after 7 8 miles itll just do the junk that its allready doin. its only getting colder here and i kno if i take it to ford theyll say its everything and then some on top of what they break like snaping the bolt for the head in my dads truck then charging us for them to remove it

 

Such a strange thing to hear your having so much trouble though. Im starting to wonder if its a computer issue its not uncommon for manufacturers to release updates to the software like any computer they do have bugs. But having the same issue on two different programs seems highly unlikely. you may try a junkyard PCM to see if it helps they can usually be had for 20 or 30 bucks and you can always sell it to someone else if it doesn't fix the issue.

 

ya could be but all 4 junkyards around me dont have a single auto ranger there allllllllll sticks
trust me ive been shifting gears vis the push pull cable under the dash bcus my shifter shaft on the column snaped.... but im runnin out of ideas now

 

try ebay or LQK online they have huge inventories at a pretty good price

 

im going to change the iat sen and clean the maf and see what happens

 

Sounds like a good start man easiest and cheapest fix

 

more details when i start it up when its below ten it has a really rough idle and its rough for the first 5 or 6 miles of driving and then goes back to bein its usual ***** self when its cold
and it feels like im losing power more and more