4.6 intake manifold help

[Zim28]

Hello,

I have a 97 GT with a pretty much stock 4.6. Anyway last summer my intake manifold cracked around the thermostat housing. Well I bought a new replacement manifold, one with the updated aluminum water crossover. I switched this out but the car has never ran as good as it did before. The manifold was the correct part number for the application. I have taken it off several times since but can't seem to get it running as good as it should. I changed the plugs, the PCV valve along with this manifold as well. My car now burns a little oil. In fact when ever I take this manifold off I can see where oil is coming in through the throttle body, through one of the lines in it. Though I can drive it fine, it burns more gas, idles pretty roughly (people sometimes think I have a newer cam) and has quite a bit less power.

Though I like to do my own work on my cars, I understand there are points where my knowledge ends, and I have hit it on this. I probably will have to break down and take it into a shop. I just don't want to have to pay a huge bill if it is a simple setting that I just don't know about. Thanks for any help.

[Zanzer]

Did you replace your intake with a PI intake?

[Zim28]

Thanks for the response. I am pretty sure it is a non-PI intake. After reading a little more about it from the link on your signiture I may try that. That forum states that you should be able to do the conversion for around $300 or so. Considering I paid $400 for the intake I bought to replace the cracked one. I still don't understand why I'm burning oil now, though. I don't think the PI cam/manifold switch will fix that. I don't want to change the heads on it, as that would entail more money and more down time for my car. I need to drive it as my only other ride is a motorcycle and its still to cold out to ride it to work.

[surfbeast]

Do a compression test. It sounds like you may be getting blow by with excess oil in the T/B.