I also have a '98 with NPI heads and installed the PI intake on it about 5 years ago now. You don't need adapters, only a dab of RTV in the coolant ports along with PI gaskets, and the PI heater tube. Gained 10-15 RWHP with the swap.
Aha, Mr Burns.. I used the injector service you recommended (InjectorRX in Houston, TX - a very good service BTW)
Yes, I lubed the "o-rings". The difference between the Dorman injector cavities and the stock injector cavities is vast.I wonder how the injectors can possibly seal. It also makes me wonder what other shortcuts were taken by Dorman (they didn't machine and provide inserts for the COP hold down screws, for instance).
Perhaps I should have paid the hundreds of dollars difference for a Ford part ? That is why I asked this question. And thanks for the responses.
I wish I would have known about InjectorRX before. I changed the o-rings on my injectors, but it would have been nice to get them cleaned and done through them. They aren't too far from me either. Oh well, I have them bookmarked now. Thanks!
Isn't the FRPP PI Intake less than $200 at most places? At least that's what I've seen. I picked up a Dorman NPI one from O'Reilly's for close to $300, but I just saw it on Summit's site for a little over $200.
I also have a '98 with NPI heads and installed the PI intake on it about 5 years ago now. You don't need adapters, only a dab of RTV in the coolant ports along with PI gaskets, and the PI heater tube. Gained 10-15 RWHP with the swap.
I heard about that method as well after the install. I went with a stock replacement for now 'cos it's my DD and I needed it fixed quickly and without any further potential issues (I also didn't know about the PI/NPI intalls at the time). Once I finish up some other things that need attention, I'll be looking at either doing a complete engine swap or rebuilding what I have. If I keep what I have, I'll be getting new PI Heads and a PI Intake then.
Thanks to all who replied !! This is why Stangnet is a cool site.
Now, here is a pic of my (formerly) trusty intake. You can see (sorry I had to shrink the image for this site, of course) The squared off interface for the injectors.
On the Dorman piece (and I'll leave it at that), the interface is kind of "cone shaped" , like an inverted volcano.
To get the car running great again should I just "hammer" the injectors into the volcano, or order a new manifold. the vendor probably soes not want a return since this manifold is now "used".
PS My internet connection was down for the day - sorry for the delay !
I would not take a hammer to the injectors; that is just asking for trouble. Have you tried tightening down the fuel rails some to make sure the injectors are all seated properly? I can't remember if my Dorman Intake had coned shaped interfaces or not, but I'm sure they did. I'm sure someone else more experienced than me will chime in, but it seems like if you had an issue at the injectors not seating properly, then you would have a fuel leak there. If you don't have any fuel exiting out near this area, then I would say you don't have a problem there (other than maybe a bad injector).
How many miles are on the car? Have you changed the PCV valve? If not, I think this can cause idle problems as well. If you have a friend with a 'Stang, see if you can borrow someone's IAC Valve to see if that is the problem.
I would not take a hammer to the injectors; that is just asking for trouble. Have you tried tightening down the fuel rails some to make sure the injectors are all seated properly? I can't remember if my Dorman Intake had coned shaped interfaces or not, but I'm sure they did. I'm sure someone else more experienced than me will chime in, but it seems like if you had an issue at the injectors not seating properly, then you would have a fuel leak there. If you don't have any fuel exiting out near this area, then I would say you don't have a problem there (other than maybe a bad injector).
How many miles are on the car? Have you changed the PCV valve? If not, I think this can cause idle problems as well. If you have a friend with a 'Stang, see if you can borrow someone's IAC Valve to see if that is the problem.
Thanks for the reply. That's a valid point about the PCV valve ; I did change it a while back, though.
Here is an UPDATE:
I found the huge vacuum leak. A vacuum hose runs from the rear of the throttle body and makes a junction with another hose on the passenger side valve cover (down, and to the rear). That hose looks as if it leads to the HVAC controls.
Thanks to all who replied. Thanks also go out to "RedDaemon" for his excellent writeup and pictorial !!
Next time, I'll ping you guys for opinions before I buy any engine part/accessory.
With the dorman make sure your using ONLY The oring to seal it. You dont need a gasket when using the dorman intake. I had no problems with a dorman on nonpi.