In another post I talked about how the truck dies without me feathering the gas and how I can't find what's wrong. Well I had it at the garage today and they couldn't figure it out either. So the mechanic brought up the known problem of the intake gasket. Since once the motor warmed up it ran better, with a lower than normal idle but no foot on the gas. I'm hesitant to try this as the truck is not kicking out any lean codes. Can this gasket fail without any codes? He suggested I change the upper not the lower and see if it solves the problem if not they can do the lower then. $300 for the upper and $300 for the lower.
I'm not sure if i can change the gasket myself or how long it would take. Any suggestions? You think the mechanics right? And which gasket usually fails the upper or lower?

 

Mine failed and threw no codes. Idled rough, would kill when slowing down, all the things you mentioned in your other posts. It was easy to do, it's just a matter of removing the upper intake and fuel manifold. I changed mine in about an hour and a half.

 

my intake gasket failure was the fuel rail gasket between the fuel rail and lower intake, i had bought the whole set so i changed it all to be safe, i also had a leaking drivers side valve cover gskt. all is good now. i spent the day on the job but i also did a compression test& tune up. remove the hood for this one, it's not too hard with help and its well worth it. you aint banging your head and you get better light to see with.

 

Where'd you guys get the gaskets from, Ford or somewhere else?
How much did the whole set cost, or could you just get the gaskets you need?

 

When i changed my upper gaskets i got the upper intake gaskets from ford and fuel injector o rings from an auto parts store. I think it all cost about $30?
Here is a link to a write up i did about changing the upper gaskets.

https://www.ranger-forums.com/forum2...ad.php?t=27084

Since then I have also replaced my lower and valve cover gaskets. It helped to replace the upper gaskets but my problem was finally fixed when i replaced the lower.

 

I got mine from NAPA

 

I read your write up when I did a search for this. It was great, I actually printed it out to guide me through it when i do it tomorrow.

Funny thing is I picked it up from the mechanic today and it drive fine so brought it home and changed the IAC and tightened down the intake bolts and it's been running great. It's supposed to get down to about 5F tonight so when I start it tomorrow I should see whether or not this did the trick. Either way I'm still changing the gaskets but I may be able to put it off a little while, or at least till it warms up a little.

No parts store have the gaskets in stock around here so I'll have to wait and see if the local Ford dealer has them in the morning.

 

I started the truck up this morning and it ran great and idles at around 7500. ut about 12 miles on it and very smooth. I have a few errands to run so I'll see how it performs after I have to keep shutting it off and starting.
I'm still picking up the gaskets since there only $9 total from the Ford dealer. But I'll put off changing them until it warms up a little. It's 8F right now.

 

Do yourself a favor and pick up a new fuel rail gasket while you're at it. As I referenced in your other thread, the '97 4.0L OHV is prone to fuel rail gasket leaks. I'd even bet that the fuel rail gasket is the one your mechanic is talking about because it is specifically addressed in a TSB. (The fuel rail gasket is often referred to as an "intake" gasket).

 

I picked up the fuel rail gasket also. So when i do go to change it I'm doing them both. The trucks been running great as of late so I'm hoping it holds out till spring, if not I'll be doing it in the cold.

 

the whole gasket set from autozone ran me around 70, had to get the valve cover gkts seperate, but get this, the valve cover set came with a fuel rail gskt. i wish id have tried gaskets first, i changed every sensor on the motor before i went the gasket route. i saved all my old parts, so i should be good to go for quite awhile on electrical parts. i painted my valve covers chrome while i had 'em off. wish the aftermarket would build V6 valve covers. hard to see with all the stuff on it but heres what my 4.0 looks like:

 

I've heard of people spraying something around the intake. Maybe carb cleeaner. If you spray it and the idle changes, it can confirm a leak.

 

I heard this also, they say it works better on a carbed motor though. I've been having 0 problems so i'm waiting it out.

 

i tried that on mine, but my vac leak was so bad thet it didnt make any difference what i sprayed on or over the motor. i was dead convinced i had a sensor problem-until i had changed out every one and only left me with 2 options, main control computer or intake gasket leakage. kinda glad it was a gasket, what with that being a problem area, now i never have to worry about that again.