4.0 Help

[BIGSTIC]

So I am new to the forum and am looking for some help. I am well versed on older big block and small block engines but this 4.0 has me stumped. It is out of my fiances 92 XLT and it has around 180,000 miles on it. When we got it this summer it ran great but now it is gutless. I am lucky if I can get it to hit 70 on the interstate and if there is a head wind well then don't even think of it. Also milage is around 16mpg which seems low for a 4.0 liter. I think it is running rich but don't know how to check. Please give some advice before it heads for the shop to get looked at.

Also is it worth it to swap in a mustang 5.0 into it for daily driving. And what kind of aftermaket soup up stuff is out there for the 4.0???

Thanks for the help and I plan on stopping by here more often now that I have an Explorer.

 

[Jason_25]

No, the 5.0 swap is not worth it at all.


Test the fuel pressure at the test port and compare it to the stock specs. You can find them in the Haynes manual. Sounds like your Fuel Pressure Regulator has failed.

 

[Alec]

Yup. Also clean your MAS. Might be time for new O2 sensors also. The 4.0 OHV is a great motor. There are bolt-ons available; the first things I recommend are usually an intake kit and catback exhaust.

Welcome to the site! If you go to the Sport Trucks section > the Need for Speed forum, I have a thread at the top with some of my performance mod suggestions.

 

[BIGSTIC]

Just thought I would let you all know. The shop called and I have two cylenders that are mushrooming their heads. So know the little lady gets new valves and probably new heads. Guess that is what I get for getting a rig with 180,000 miles on it. Oh well I guess now I won't feel bad about dropping even more money into her over the long run.

Later

 

[Alec]

I'd go ahead and get a mild cam and computer upgrade then. Might as well do the cam while doing other engine work.