Ordered my injectors...

Shudders under light load, won’t outrun Meatloaf on a scooter. My LTFT has been running +10-14, two known good O2 sensors verify it. New fuel pump, filter, maf. Absolutely no vacuum leaks. Nearly 200k and I’m unsure if they have ever been replaced. Please encourage me that I didn’t just blow 280 bucks....

 

If there’s one thing I’ve learned is make sure the parts are OEM, I had two different MAF sensors aftermarket that I thought were OEM and my trims were +15 -15,
Ended going to the dealership and got an OEM MAF and replaced the fuel pump and now my trims are at ZERO.

Never had injector issues ever with 600k

 

I have two known good OEM mafs, and have been chasing this problem for some time now, when I had the throttle body out last year I cringed at the goo inside the intake plenum, I’m suspect at least one of the injector tips to be crudded up. Without a vacuum leak it has to be in the fuel delivery. She wants more. (At least this is my understanding. Pray for me.

 

Was it the fuel pump or the maf? A weak fuel pump will drive up the ltft too. But I agree 100% on OEM parts. I have thrown many nutties due to that crap, trying to save a buck

 

1) fuel regulator
2) fuel filter
3) fuel pump
4) vacuum leak
5) smoke test
6) exhaust leak before 02 sensor
7) air filter
8) MAF sensor
9 02 sensor


All these check out ok?

 

Was definitely the MAF that caused most of the problems.

With the new fuel pump I got better pressure at full acceleration and needed less methonal as added fuel

 

Are they really sold individually?! I think I need to sit down....

 

Methanol?!?! Lol, this old mofo just wants to keep up with traffic

 

Yup. I’ve been through it all. If this doesn’t fix it, I will hire someone to tow me on the freeway and on long hills as I hold a pinwheel out the window

 

Yeah, you can buy one or a bazillion

 

Bad knock sensors will make your truck run like meatloaf FYI

 

Be sure to post pictures of your new compared to old. Your current injectors are brown tops. Right?

Without anybody seeing your truck, I haven't seen a definitive "silver bullet" answer. Whatever the issue, you will be the one to find it.

I've been very happy with the new FJ585s from Rock Auto that I installed a few weeks ago on my 3.4L. It just runs a little better than before. Nothing earth shattering, just a little more responsive.

Roughly 10 years ago, before I discovered Rock Auto, I bought a set of SMP/BWD Intermotor injectors from O'Reilly for an 8 cylinder at $125 each.
That was over $1,000 with tax. It was expensive, but they still perform great after all these years. No regrets.

Here's what happens to counterfeit OEM injectors from Amazon. The pentile caps start to melt and deform. One melted, deformed, and became stuck in intake manifold. The top o-ring started leaking fuel all over the engine. This is what cheap garbage from China looks like after 1,500 miles.



I've witnessed and personally experienced an increased likelihood of coil failures on injectors over 20 years old with 200,000+ miles. As you can see from the diagram, there are electromagnetic parts inside a sealed injector unit. Sure, these can be cleaned. But there is no process for opening a sealed injector unit to replace the coil, spring, and valve parts.

 

Yeah, the Intermotors from RockAuto were 70 bucks each; interestingly enough, they are being shipped from 3 different locations. You would think there would be a dozen of these things at each warehouse. The Plenum gasket is coming from yet a different place. Another reason I suspect this is my problem is that the truck was in storage for two years, who knows what the ethanol did while trapped in the injectors it hasn’t been right since I’ve owned it.

 

This honestly sounds too much like a vac leak for it not to be, every symptom. Those LTFT aren't so far off that an injector or even two have stopped working.

 

I wish the OP was near by. I bet I could find the issue in less than an hour.

 

I have smoke tested and actually plugged off all vacuum sources. Trim stays high. There are no exhaust leaks. Trims are high regardless of throttle position. Are you trying to give me a complex? Lol

 

Check the PCV valve gasket or hose for a leak or defective valve

 

I just replaced my injectors with reman from Motor West. My problems weren’t as bad as yours but it did smooth out the engine and fix some of my rough idle. I have about 300k on this engine.
Before doing all this I did check fuel pressure and fuel regulator.
while in there, I removed my intake manifold and replaced both knock sensors and the knock sensor harness. This was very worth it because the old harness was basically melted!
If you go that far, you will need 2 intake manifold gaskets, 2 plenum gaskets, and some black etc for the heater crossover pipe. I would also get a roll of Tesa wire harness tape because your injector harness holder (grey plastic) will probably crack apart when you start disassembly.

 

By the way, I bought the sensors and harness on eBay. They appear to be legit OEM.

 

This is really good info and stuff. So you didn't have any MIL codes or anything right? Just running rough(age and all 300k miles)?