Idles rough at start

[foundrykid]

Ok, so in the last week, the old girl started to idle rough at startup, and seems to cut out ounce in awhile as i drive. Its a 96 XLT 4.0 WD. Also wanted to note that in that week, the fuel pump had died, replaced that, (sucked FIY). Also, have changed crank shaft position sensor, coil pack, fuel filter. At the very least, she starts up now thanks to the new fuel pump, but still idles rough for the first 10-15 seconds at startup, and cuts out as i drive. Could it maybe be the cam shaft sensor?

 

[EricM9104]

I was having the same issue, what kind of spark plugs do you have in and how old?

 

[McSlug]

Can be intake gaskets. This is common but not always the issue. Is your cel illuminated.

 

[foundrykid]

plugs and wires were both replaced last summer, were nothin special, prolly about the cheapest autozone had to offer to be honest.

 

[joe doe]

mine does this too .lets get this thread going .
first 10-15 seconds mine feels diiferent .then it smooths right out after that .
drives fine .just that first start thing .
i just had all my gaskets replaced
head gaskets
intake gaskets
upper plenum gaskets
head bolts
2000 4.0 ohv 135,000

 

[EricM9104]

mine does this too .lets get this thread going .
first 10-15 seconds mine feels diiferent .then it smooths right out after that .
drives fine .just that first start thing .
i just had all my gaskets replaced
head gaskets
intake gaskets
upper plenum gaskets
head bolts
2000 4.0 ohv 135,000

Mine does the same.

OP, check your plugs.

 

[foundrykid]

just pulled the front of the intake off for ***** n giggles, found something bad. Instead of a nice clean interior intake, i found it caked with fluid. Since it seems pretty burnt, i cant tell if its oil or transmission fluid. It doesnt smoke when it runs. Doesnt seem to burning oil. And i wanna say it may have a slightly reddish tint to it. So I really want to rule out oil. But cant tell for sure. Wondering, could this be much of my problems??? Maybe a bad transmission modulator? Could explain the rough idle at start. The shifting issues. Vaccum leak. Only problem is, i cannot seem to find the modulator on the transmission.

 

[joe doe]

i was wondering if these had a vaccuum modulator too?


do they?i have a 2000 ohv v-6 with auto.i recently changed my trans fluid though,but had my mechanic do it .i,ll ask him if they have a modulator.

 

[foundrykid]

well, found a bad spark plug. learned a valuable lesson, dont go for the cheapest plugs in the store. Apparently they're that cheap for a reason. Got me a can of Sea Foam to run through the intake, smoked like a mother*****, but seemed to smooth the engine out quite a bit. gonna pull the intake and swab her out real good this weekend, try adjusting the bands in the transmission, and any other odds n ends i can tinker with. Lord knows there's plenty of that to do, lol.