K - I've been diving through this forum for some time to try to diagnose the problem with my 4runner. I've found and repaired the problem, but wanted to share my learnings back with the community.



Here's the scoop:

• I had a fuel injector that was dead. My truck was not firing on cylinder #6.
• I ordered remanufactured fuel injectors & replaced all six injectors thinking if one went bad, the rest may follow (and I already went through the work of removing my intake plenum and fuel rails).
• My truck ran great! - it Didn't, however, start so well.
• The car always fired up on the first start of the day. If I ran the car and let it sit for a while, (let's say 10 minutes to 5 hours), it would take between 10 and 20 seconds of turning over to catch when starting.
• I read this could be numerous things - CTS, IAC, MAF, Fuel Pressure Regulator, Fuel Pump, Leaking Fuel Injectors.
• I thought for sure it couldn't be the Fuel Injectors - I just replace them. This was, however, the only thing different on the engine since the problem cropped up.
• Well - I replaced all six fuel injectors again, and it fixed the problem!

According to what I've learned, if a fuel injector is leaking, it will typically do so when the engine is warm. Additionally, and more importantly, the fuel rails will lose pressure and, when the engine is warm, the remaining gas in the lines will vaporize - causing a vapor lock (yep - vapor lock in an EFI vehicle). This obviously makes it more difficult to start the vehicle since gas has a difficult time getting to the cylinders.

I will post photos of my step-by-step injector replacement (without draining the coolant fluid) soon.

Thanks everyone.

97 4runner Limited, 150K miles, 3.4 L V6

 

Hey, very interested to see how you replaced the fuel injectors. You just diagnosed my problem with my runner....thanks

 

Also, when replacing the injectors, the grommets are VERY picky. One small pinch, misalignment, or lack of pre-lubing and they will piss fuel. If you pinch the collant hoses with some vice grips before removing them you should only loose a few mililitres of coolant.
Good stuff on the fix as it can be a pain dealing with the fuel system.