It could be a bad catalytic converter plugged up. Check for codes for this.

To be sure, you should check fuel pressure again, and get us the numbers.

Had the code checked again, it is still only "PO300 cylinder misfire detected."

Put the fuel pressure gauge on the fuel-rail tap again and here are the exact numbers:
With the key in and the ignition set to on position, engine not running: 42 psi
With the engine running at idle: 40 psi
With the engine revving at approx 3,000 rpm: 38 psi

I found the fuel leak, which is a very tiny leak at the #1 injector. Must not have gotten it set tight upon re-installation after intake install.

So what do you guys think now? Thanks again for all your assistance!

Dave

I think it is supposed to be between 41 and 47 PSI.

What do you read when the engine is running and you disconnect the vacuum line from the fuel pressure regulator?

I tested the fuel pressure again, with your inquiry in mind, here are the results:

1. ignition on, motor not running: 40 psi
2. motor running: 40 psi
3. motor running, vacuum line on fuel pressure regulator removed: 46 psi
4. motor running, vacuum line replaced: 38 psi

What does that tell you? Is the fuel pressure regulator bad (seems like it is having something to do with it)? The fuel pump not up to snuff or the fuel filter maybe not flowing perfectly?

Also, there is a small amount of fuel leaking from the base of injector #1, is that simply a bad o-ring or does that mean something is up with the injector/compression off due to leak?

Thanks,

Dave

Edit by CathedralCub: IGNORE THIS POST per the next post

If the fuel pressure is supposed to be 41-71 psi and I have 40 at idle and 38 when the regulator'* vacuum line is removed (and it should be higher), then I know the regulator is bad, and there isn't enough fuel getting to the fuel rail, so that is the fuel filter or the fuel pump correct?

The leaking fuel injector couldn't cause that fuel pressure drop correct? I mean it is a leak that simply gets the aluminum where the injector is set and doesn't spray or run at all, though I will be resetting that one with a new o-ring to insure the leak is gone. I cannot imagine it lowers the pressure much at all.

I'm thinking replacing the regulator: yes, the filter: why not, and then see what'* going on?

Dave

IGNORE THE POST ABOVE, I WASN'T THINKING STRAIGHT (DISTRACTED)

If the fuel pressure is supposed to be 41-71 psi and I have 38 at idle and 46 when the regulator'* vacuum line is removed, is that a clogged filter (it'* six years old) or is it the fuel pump?

The leaking fuel injector couldn't cause that fuel pressure drop correct? I mean it is a leak that simply gets the aluminum where the injector is set and doesn't spray or run at all, though I will be resetting that one with a new o-ring to insure the leak is gone. I cannot imagine it lowers the pressure much at all.

Dave

I replaced the fuel filter, but the psi readings of 38 idle and 46 with the vacuum line off the regulator on idle stayed the same.

I'm thinking fuel pump.... sound right?

Wait, slow down . . .

Okay, so here it looks like you typoed the 71 then ran with it.

Not unless it is gushing.

No.

46 with no vacuum and 38-40 with vacuum should be okay. Remember: Vacuum is backwards. When you push on the accelerator and vacuum goes down roughly relative to throttle opening going up. This is really handy for stuff like fuel pressure regulators as you need less fuel pressure to idle than to accelerate. When you disconnect vacuum from the pressure regulator, it is acting as if you are at wide open throttle and allows full pump pressure through. In my book, the regulator is acting okay and the pump is okay enough.

A couple of questions:

How is the air filter doing?

Have you test-driven the car since replacing the fuel filter?

I wish I could, but my daughter has my truck and I need it back, haha. The old adage, "my ox cart is in the ditch" fits the bill here.

I had the vac line on/ off backwards on the one post, woops!

The air filter was replaced with the plugs and wires under 100 miles ago.

And yes, I didn't slow down and I replaced the fuel pump after looking up the specs and didn't know if the recommended 41-47 was at idle or also the range for under load. Nice thing is I got a good workout in, the less than nice thing is the fuel pressure readings are identical.

I test drove it for a quick spin (just had 5-6 minutes to spare) and she flew up the hill as hoped when she was cold. But she did have one moment where the
acceleration fell off on a flat part of the road without pedal position change and I pushed the pedal to get it back to accelerating. Marked improvement when it was cold, but I think I need to get her hot and see how she goes.

Could this be a CAT? I don't want to purchase one of those as I have no angle to get cheap parts, and I last heard they are expensive... uggg.

1,000 thanks for all the assistance!

Oh, the service engine light was off, BTW. Maybe simply because I disconnected the battery to install the fuel pump?