My 91 4runner just developed this problem. The first time I start it in the morning it starts really hard. Like maybe the fuel line is draining back into the tank? Once it's started, it's fine till the next morning. Also, what's the easiest/best way to put a fuel pressure gauge on this engine? Thanks for any advice.
The first thing I would do is check to see if the cold start injector is working. There is a section of rubber fuel line just above the driver's side fuel injector rail up near the distributor, that is probably the easiest place to put a fuel pressure gauge. It doesn't sound like a fuel pressure problem though if it is running fine the rest of the day. My suspicion is that now that it is a bit colder in the mornings the cold start injector isn't giving you the added burst of fuel it needs when the engine is cold.
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