I have a 92 F150 XLT, 302 cu in engine with 4WD, 8 foot bed. I put in a Spectra Premium fuel tank assembly for the rear tank. I have 2 tanks on my truck: one in the front and one in the back that I replaced.

The symptoms when I switch to the rear tank are rough running, slight backfiring, poor power and acceleration. When I switch to the original Ford front tank it runs fine again almost immediately.

Question: Is it bad gas or a bad fuel pump? I suspect it to be the Spectra fuel pump because it is "made in China" as is the rest of the tank. It is only 1 year and 9 months old. I put in 3 cans of "Dry Gas" in the tank and can't see much of a improvement.

So how can I determine what the problem is? I guess I can drain some gas out of the rear tank and see if I have water in it. Is there a better way to determine if it is the fuel pump or water in gas?

Regards,
Larry

 

id check the pressure and if it holds it.

 

How do I do that? What equipment do I need and where do I put the pressure gauge?

Regards,
Larry

 

A fuel pressure gauge, with a Ford fitting . Schrader valve on the fuel rail is where you attach it . Easy.....

 

Thanks JWC 3! I will follow your advise and get the equipment I need to check it out.

Regards,
Larry

 

Thanks for the response. It lead to the answer I needed.

Regards,
Larry

 

So what was it? I'm having the exact some symptoms with exact same part on mine and I'd appreciate the help

 

Hey Truck Guy99, so far as I can tell it probably is just water in the gas. I had the problem for two weeks now. Put several cans of dry gas in the tank and it didn't seem to help much, but 2 weeks later the problems seems to have gone away. I didn't get a chance to check the gas line pressure as was suggested by other posters. The truck runs normal now. Could be all the water was sucked out by now.

I do notice the weather getting colder and that means temperature in the tank will be colder too so maybe the fuel pump was overheating. Don't know without checking the fuel line pressure.

Still it's hard to check the problem when the symptoms are absent.

So right now, I'd say water in the gas did it.

Regards,
Larry