on i got a 90 f150 with a 4.9 t18 4 speed 75k original miles. its got fresh tune up cap rotor plugs wires oil filter vac lines cleaned out throttle body air filter clutch prssure plate fly wheel starter pcv valve slave and master cylender with new hose new trans and rear fluid fresh breaks all around with new rotors n drums ect.

got one prob when i first start it in the mornin it will idle rough and or stall but ill start it back up n tap the gas n its fine but it only does it in the mornin. but some times when i shift 3rd to 4th it hesitates a little but only for a split sec.

any one have any ideas the only thing i havnt replaced yet and the only thing i can think of is maybe the distributer and or the modual on the side.

 

also in second sometimes its real slugish till i shift into 3rd

 

Why did you replace the vacuum lines & starter? Did this symptom appear before or after all that stuff? Have you ever checked the fuel pressure or ignition timing? Read these captions:

.

 

before. timeing is spot on set it the day i bought the truck but never checked the fuel pressure

 

the the ring gear was bad so i replaced the starter for good measure when i put in the new flywheel and all the vac lines were dry rotted

 

Then are you sure you got ALL the vac lines, and are you sure you routed them correctly? Did you use the map under the hood? It doesn't show the HVAC lines.

Don't replace any more parts until you find one that fails a published test. Get a Haynes manual & a digital multimeter, and follow the ignition diagnostic procedure in Ch.5, usually Sec. 5 or 7.

 

yeah all the vac lines are on the corect way ive had 6 of these trucks in the past 2 years ive replaced the vac lines on a few of them n had no prob

 

Read this thread:

http://www.fordf150.net/forums/viewt...p?f=21&t=97221

 

my fuel pumps fine. n my truck will stall at first unless i give it a lil gas then it straitens out n is fine and can drive it all day. i drove it 300 miles the past 2 day n its fine runnin but when u start it in the mornin it does it. but i can start it up n shut it down n let it sit 8 hours n it will start fine its just first thing in the morning and my check engine light dont come on. and yes the check engine light does work when u turn the key on. and no burnt electrical smell

 

1. EGR valve or EGR position sensor
2. IAC valve
3. MAP sensor
4. Ignition coil or Ignition control module
5. Bad fuel pump

http://www.autozone.com/autozone/rep...ge=symptomBody

Steve83,

I see you hang out over here as well as NLOC.

James

 

i have a iac valve and egr valve from my old 88 so ill put them on tomarrow and see if that fixes it

 

i just put the new iac valve in and i didnt put the egr vale in but i did put the egr possition sensor in and i started it up and it stumbled a little but didnt stall but it catched itself right away n seems to b idleing better so ill check it again in the morning and see if its any better or the same. the feul pump is fine. my uncles an ase mechanic he says the ignition modual normaly is either good or dont work. so the only thing i havent done is the map sensor

 

Clean the fuel injectors!!!!!!!!!! The early 4.9s were notorious for dirtying up injectors. I used a container with fuel and a concentrated cleaner hooked to the fuel pressure port with both fuel lines removed, and blocked. Just did one a few months ago and had to clean it three times. It was barely running when it got here and has purred like a kitten since.

 

I skim through 4-7 BBSs each day.