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Q: losing fuel pressure when it warms up

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I have a older carbourated 22r swapped into my 4runner I was driving it and it started spuddering on the highway so I checked the little window on the front of the carb and it was not showing much fuel so I replaced the fuel pump and filter and the lines and I cleaned the tank out and tried to run it but once it warms up it loses fuel pressure starts and runs fine for like 10 minutes but then it loses fuel pressure so my question is what could be causing this

My car has 60000 miles.
My car has a manual transmission.

Hi there. This can be a very difficult item to diagnose. In some cases, the lack of fuel pressure is caused by a restriction of fuel in the system; from the pump itself to all lines or the carburetor. It can also be caused by an exposed wire or faulty ground, vacuum leak issues or even primary jets in the carburetor that are clogged. It is probably best to check all vacuum lines first, remove and completely clean the carburetor and possibly the electrical connections to the fuel pump to be safe. If this doesn’t clear up your problem; it’s probably a good idea to have a professional mechanic complete an inspection with you, to help you resolve this pesky problem.

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