Pulling my hair out...I hope this is just an injector! Input requested!

Hey guys, a quick background on the situation. I started heading home from work last night and I noticed the car felt a little notchy as soon as I accelerated mildly from the parking spot. By the time I go home, every time I would accelerate, with or without any boost, it would stutter and felt like a bunch of misfires...like spark blowout, but at way low rpms. It does this only under a load, but it does not need to be 100% load. I pulled the plugs last night to see if there was anything obvious, but the only thing out of the ordinary was a black plug in cyl. 4. I replaced the plugs and still have the same issue.

I will be diving in tomorrow and swapping the injector out to see if that does anything, but does anybody else have input?

The coils were new <30k ago. PTU was replaced and has about 80k on it. Plugs are new as of last night...new fuel lab mini FPR. Car has a hotwired supra pump. Wires don't even have 60k miles on them.

Would an injector that is stuck open do this? Do note that it won't do it unless the car is under a load. What else should I be checking if the injector doesn't fix the problem?

Ah the stutter...can be so many things; in the air, spark or fire systems.

Things I would check first/do next you didn't mention:
upgrade fuel pump
ECU look/smell
MAF
intake pressure test

Damn the stutter! DAMN IT TA HELLLL!

...ok, with that out of my system, I have a "Supra" pump in the car already. How can I check the MAF w/o just looking at the honeycomb for abnormalities? I will definitely take a peek at the ECU. Thanks for the ideas.

its spark related, wires, coils or something like that

If it were the coil, wouldn't I have found two black plugs? Any way to quantitatively test the wires? ECU is good...just finished looking for any leaks/damage.

Quote:

---

Originally Posted by MADMarc

Damn the stutter! DAMN IT TA HELLLL!

...ok, with that out of my system, I have a "Supra" pump in the car already. How can I check the MAF w/o just looking at the honeycomb for abnormalities? I will definitely take a peek at the ECU. Thanks for the ideas.

---

You have fuel pressure gauge? How old is pump? Only way I could tell my maf was bad is replacement with known good 1.

Sent from garage

Are you throwing a CEL? It could easily be a stuck injector. Is it a TT or NA? Different injector types of course.

Thanks a bunch for the posts, guys. Pump doesn't have 100k on it and my fuel pressure gauge says it's holding well. No CEL, though. Not even a pending code...weird. It's a TT, so I'm trying to snag a single 360 from someone local. One of the guys on SoCal said I can borrow one from his parts car, but I've got another friend who lives a few miles away that is trying to dig one up...not driving fifty miles in my old pickup for the injector sounds like a worth while wait.

...and Jim, I still want your car ;)

If fp is good, then injectors. When last time cleaned/time to get 550s
Hope u have a lot of hair!
Sent from garage

lol I hope I do too! I sent the stuck 550 to RC for a rebuild (360s are in my car). If I get it back before I get the 360 injector, I think I will just toss them in with the NEO and put my new tuning shoes on.

Good luck Marc! And no, my car is NOT for sale :lo5l:

Bad idea to fix a problem with mods.

If it doesn't fix it then you have several new variables.

I have driven a 3/s on 5 cylinders. It just feels rough, it didn't stutter.

My vote is pressure test and inspect ecu.

Sent from my DROIDX using Tapatalk 2

Yeeea, perhaps it won't solve the problem and then I will look @ the PTU, wires and coils more closely...but I have been meaning to nudge myself towards putting this stuff in for a while and this was a nice nudge from the world :). ECU has been checked and is visually perfect. A gnarly boost leak doesn't seem likely to be the culprit as it comes and goes as RPMs increase. This car is a tricky one ;)

NEO is in (wow that was simple) and I just got my rebuilt injector in. Will be tossing it in HOPEFULLY tomorrow and be sure to chime in with updates for future doers.

...how about just a ride then, Jim? :D