1999 XJ 4.0 fuel injection

Good Afternoon!
During a water pump replacement, I decided to remove and weld my cracked and leaking stock ex header. I was amazed at how much raw fuel and gunk/carbon was in my intake ports of the head and intake manifold. I have 60+ thousand miles on the engine and it has always been a gas hog. Three intakes look better than the other three and the corresponding exhaust deposits look better. Should I consider replacing the injectors or is this just more par for the course Mitsubishi stuff ???? How do u test these things or can u test these things???

any insight is welcome.. :read:

Thanks

Run some Seafoam through the intake (the brake booster vacuum line).

Lol.. After I posted the question, I started looking around the sitE and your name popped up in the reams of info I found here. I feel a little backward about not having looked first , but maybe it was humorous to some... So... Before I ask... I'm gonna google sea foam and if it is some sort of male enhancement thing then I'm gonna get a laugh out of it too...
Thanks for the help and the post you already shared on the topic..

Btw.. It's mostly paved donkey paths here in mountainous terrain... I'm getting less than 9 mpg.. I have no idea what my fuel pressure is but ill find out and I'm looking for smaller cc output without a too lean or hot burn... Called RC injector and left a message...

9mpg is bad. Start checking the sensors. Dependent on the age I would flat out replace the O2 sensors. Don't fool with the injectors yet. If the system isn't operating correctly smaller injectors won't help. I don't know what this has to do with Mitsubishi.

I would like to preface my comments/questions with I don't mean to hi-jack but I can't find the answers to my questions anywhere else.

I am getting bad MPG's as well.

So I replaced my cracked manifold with an APN manifold. http://www.amazon.com/Jeep-Exhaust-Manifold-4-0L-Engines/dp/B00566GILI/ref=cm_cr_pr_product_top

No difference in MPG's. So I replaced my factory injectors with some Neon 703 injectors http://www.naxja.org/forum/showthread.php?t=1101279

Still no difference in MPG's. I understand that there should be a difference in miles to a tank of gas (given I now run on 33's), but the MPG's are still very low. around 13 or so. Is this normal considering lifted XJ running 33x12.50x15's and 3.55 gears with an AW4?

My other question: Is there a way to test our (98 Cherokee sport) Fuel pressure? I get a very bogged down start-up, sometimes it just cuts right back off. It also has a hesitation (bumping back and forth) when going up hill and trying to give it more gas to keep my speed up (say 55mph or so).

Thank you Talyn. The Mitsubishi comment is from reported info that my motor is a Mitsubishi product. Very powerful and long lasting but an Incurable gas hog.. I do not KNOW, this to be true... It may not even be true the engine is a Mitsubishi product, but it is a dyed in the wool gas hog. But, if you step on the accelerator pedal hard... It jumps like a doped up sprinter.. Just wish I could get the mileage up.. I'll check or replace the 02 sensors and any others I can.
Thanks for the help

The 4.0L has no relation to Mitsubishi