X66P Upper Engine & F.I. Cleaner (88861803)

Anyone use this stuff? It can't be dumped into the fuel tank and has to be fed through a fuel injector cleaning device. I wonder if it could be introduced to the engine through the brake booster like Seafoam?

I have a P1174 code on my 4.2 that will not go away. Here's what I've done: replaced both Oxygen sensors, replaced all plugs, cleaned throttle body, ran several different brands of F.I. cleaner through gas tank, use 89 Octane, replaced thermostat (yellow sludge moisture was forming in intake resonator before this due to low temps) . I might try Seafoaming but this stuff looks like it is directly designed for my issue. Any thoughts?

mrrsm

You don't mention having replaced the Fuel Filter yet. but it might help doing that before trying any "Through the Tank" & "On the Vehicle" BG-44 Fuel System Cleaner and use the BIG Bottle of Chevron Techron EFI Cleaner as it is probably as the strongest of the lot. You've probably already tried most of these. but for the sake of your Readers who might want to know more about what is being suggested as good, this article provides a good background:

Alternatively, after you change the Fuel Filter and before you decide to go through the complicated and mostly ineffective GM Top Engine "On The Vehicle" EFI Cleaning Procedures, consider filling the tank to the brim with Chevron High Octane Gasoline (also with Techron) at the very same time you dump in the Chevron Techron Additive and see if things improve. By the way. You should avoid using the GM TEC Additive through the Fuel Tank because in concentration settling to the bottom of the tank. it can dissolve the seals inside of the Fuel Pump :

GMT Nation's ever redoubtable and famous @MAY03LT has this excellent Youtube video on “How to Change the Fuel Filter on the Trailblazer, Envoy. ”:

"Chance Favors The Prepared Mind. " Dr. Louis Pasteur
"De Mortuis GMT-360. Nil Nisi Bonum. "
(NEVER Speak Ill. of a Dead GMT-360)

gmcman

First of all, If your PCM is stock, then I would stop using the 89 octane for now and try some 87

Reason is, to get 89, some pumps have to mix the 93 with the 87 and because of the prices, 93 very likely sits in the tank for awhile. Some stations have a tank for 89, some do not.

I have a bottle of what you have linked, and yes, it's not something you pour into your tank.

Let me verify the ratio but I'm pretty sure it needs to be mixed with 7 parts gasoline to one part cleaner. I use a spray bottle and spray into the throttle body while it's running around 1500-2000 RPM. Take a piece of 2x4 or similar and use the power seat to press against the gas pedal to hold the rpm.

Sounds like you may have an injector issue, but first thing I would do is verify ALL the intake manifold bolts are tight, even the one hidden under the molded vacuum hose between cyl 3 & 4. The bolts get loose quite often after the intake seal becomes flattened out. be careful, only 89 INCH POUNDS of torque on the bolts. 1/4" drive, 10MM socket.

If that checks out, then I would get some of this and run it through your tank.

After that, follow up with some 44K.

Believe me that loose intake manifold bolts will cause a myriad of fuel issues.

Another option is a faulty fuel pressure regulator. Unfortunately it's one of those things that you cannot easily test or even test at all, sometimes it's just good to blindly change unknowing of it's condition but the end result is knowing it's good.

I changed mine awhile back chasing some lost MPG's and it did seem to smooth the acceleration out a little, after about 12 years I figured why not.

Aside from that, you may very well need to remove your injectors and have then professionally cleaned. Try the other options first.