Floored no go
#1
07-27-2011, 08:52 PM
Floored no go
98, LS 4x4.
After changing my FPR, and my fuel filter at the same time, and pouring sea-foam down intake, I noticed in the next few day as I give it more than 3/4 throttle it half way falls on its face and barely increases speed. Everything else was fine for a while, now recently it has a hard time getting going from time to time.
First problem: As before up to 3/4 throttle is goes just fine. Not even a misfire (feeling), however, it will get up to 3000/3500 rpms its still fine, to me that rules out any fuel delivery problems. Checked plugs, look very good, changed cap/rotor, no change. With it only having the problem with the pedal pressed just so far I changed the TPS, and no change. Unplugged MAF, no change. Cats are clear, (have a exhaust buddy and he found back pressure of only .5 psi. He says, that is just fine.) So I'm at a loss.
Ive also noticed that if I do floor it, it seems to clear up a little little bit, however, I let off and can hardly go anywhere. Idles fine, but hesitates like mad. Almost as if I have no air going through the MAF, or running on a few cylinders
Second problem: After a fine start of the engine, it is just like I have floored it and let off. Hesitates and barely goes anywhere, like I am running on a few cylinders.
so to test both problems, I did a fine mist test on either side of the engine to test for arching. No light show. Sprayed carb cleaner around the intake and no change in the idle, And really a whole slew of others, really to many to list it feels like.
I am yet to test pressure only due to the fact that as I said before it will run fine at high RPMs, just not when I floor it, so I dont think that is going to be the issue. Still could be....
The only code I have gotten is p0300, random misfire.
Anyway, that is about all, as I think of anything else I have done, or tested I will edit this post or respond to q's and a's. Thanks fellas
After changing my FPR, and my fuel filter at the same time, and pouring sea-foam down intake, I noticed in the next few day as I give it more than 3/4 throttle it half way falls on its face and barely increases speed. Everything else was fine for a while, now recently it has a hard time getting going from time to time.
First problem: As before up to 3/4 throttle is goes just fine. Not even a misfire (feeling), however, it will get up to 3000/3500 rpms its still fine, to me that rules out any fuel delivery problems. Checked plugs, look very good, changed cap/rotor, no change. With it only having the problem with the pedal pressed just so far I changed the TPS, and no change. Unplugged MAF, no change. Cats are clear, (have a exhaust buddy and he found back pressure of only .5 psi. He says, that is just fine.) So I'm at a loss.
Ive also noticed that if I do floor it, it seems to clear up a little little bit, however, I let off and can hardly go anywhere. Idles fine, but hesitates like mad. Almost as if I have no air going through the MAF, or running on a few cylinders
Second problem: After a fine start of the engine, it is just like I have floored it and let off. Hesitates and barely goes anywhere, like I am running on a few cylinders.
so to test both problems, I did a fine mist test on either side of the engine to test for arching. No light show. Sprayed carb cleaner around the intake and no change in the idle, And really a whole slew of others, really to many to list it feels like.
I am yet to test pressure only due to the fact that as I said before it will run fine at high RPMs, just not when I floor it, so I dont think that is going to be the issue. Still could be....
The only code I have gotten is p0300, random misfire.
Anyway, that is about all, as I think of anything else I have done, or tested I will edit this post or respond to q's and a's. Thanks fellas
#2
07-27-2011, 09:08 PM
id start by checking the fuel pressure
check this out it might help
https://blazerforum.com/forum/tech-a...agnosis-23038/
check this out it might help
https://blazerforum.com/forum/tech-a...agnosis-23038/
#3
07-28-2011, 02:38 AM
A fuel delivery problem wont show up at high rpm if there isnt a high load on the engine.
Have you run a live data scan to see what the computer is seeing?
Have you run a live data scan to see what the computer is seeing?
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