It still won't idle, the codes say circuit 3 and 5 injector problem. I changed the harness,had 3 and 5 injectors checked they said they were good. I connected the fuel line to the rail and turned the key and bumped it a few times had a friend watch the injectors and they do work. I pulled the intake thinking I had a leak and noticed fuel in the 3 and 5 ports in the head? Engine sounds great above 1500 rpm but let my foot off the gas it loads up and dies? HELP!!!

 

have you checked the Throttle Body? Might need a cleaning....

That type of problem can be caused by a multitude of things... and it will be hard to pin-point.

Have you performed any major maintenance lately?

Any modifications to the truck?

How many miles are on the truck?

 

Sounds to me like the number 3 and 5 injectors are leaking down. Fuel in the intake ports of the head is a dead giveaway. Sounds like whoever tested them didnt do a very good job of it, they probably just checked resistance values. Try swapping the number 3 and 5 injectors around with 2 different cylinders that arent giving injector codes, and see of the codes change.

 

That is a good method.... also whenever I remove and install injectors I ALWAYS replace those o-rings... I've seen more than one engine have issues b/c the o-rings are worn/torn/etc.

A $1.00 O-ring is worth the extra few steps.

 

Ditto. Also, use some lube on the o-rings or you"ll risk cutting/twisting them when installing them. I use standard motor oil. Just a thin coating is enough.

 

They used to make a special lubricant that isn't petroleum based so it wont dry out the O-ring over time... I can't remember the name of it... but that is what I would suggest to use if you can find it.

I remember it saying "Silicone Grease"

If the o-rings are neoprene you can use petroleum based products, but if it's rubber silicone is what I suggest.

 

Did you pull those valve covers and check to make sure there are no broken valve springs. A lot of guys/threads have had the same issue where they can get it started but have to hold the gas to keep it running and have found broken springs

 

He PMed me and told me he's got a fully Built motor and heads.... so I'm gonna wait until he posts a full Mod list.... as I've got a few theories on this one.

 

Yeah, he PMed me too but I guess he didn't like my thoughts.

New engine and heads huh? That leads to a ton of questions. How old/new is this engine? Who put it in? Mileage on it? Why was the first engine replaced?

 

Yeah. I just told him to post up the complete mod list so we could start troubleshooting... a lot of factors with a built motor and heads.