4.0 continuous backfire and runs rich | Ford Explorer Forums - Serious Explorations

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4.0 continuous backfire and runs rich


Well-Known Member
November 14, 2010
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Year, Model & Trim Level
94 XLT 4.0 tow package?
I have a 94 exploduh 4.0 and it runs very rich I cant figure out what it is. there is no check engine light. I lost the gasket between the egr and the intake. thats the only thing i can think of. could that be causing it? and when i drive it it pops continuously it sounds like its coming from the exhaust but i know its the engine. please someone help?

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If it doesn't throw a check engine light, I pretty much go for the fuel pressure gauge. Possible problems would be a fuel regulator that is stuck shut, or a fuel regulator with a hole in the diaphragm that is allowing gas up through the vacuum hose to the intake manifold.

so to test the fpr what should i do?

In my signature line, there is a link for the 1s generation fuel pressure test thread. It's all there in living color. If the pressure is too high, the fpr is bad. If you suck on the vacuum port and get gas... it's bad.

ah sorry i didnt look at your signature. ill check it.

No problem, I don't read signature lines either, except Brooklyn's... that's just a library of great info.