LS1 pwrd NOVA

iTrader: (2)

Has been driving fine before but now We are having an issue on my sons 02 trans am auto 60E. It happens often or once in a while maybe when warm he said. When driving and you punch it, it doesn't rev up or start pulling, it's like nothing. From a stop and driving normal it'll pickup speed when cruising. Hoping anyone has an idea where to start looking. Cel is on but it's been on since day one. Has long tubes also... I need to pull the codes but he says it comes and goes with this issue

******EDIT FOUND PROBLEM....****

We are losing fuel pressure even when just cruising around and seems worse when it gets warm outside. When it starts messing up, it's around 20 psi. We have installed a new racetronics 255 in tank pump, hot wire kit and new fuel filter that's not even a year old yet. This pump was installed way before we started having issues.

So do you think it's the fuel pump or internal regulator that's messing up as that's all I can think of that would cause this issue.

RPM WS6

iTrader: (3)

Best to check the codes before shooting in the dark at anything else.

LS1 pwrd NOVA

iTrader: (2)

Pulled the codes, only air & other emission crap was on the codes.
So since it's cold outside it's driving fine.
When it gets hot while driving for a while it starts messing up

ragtopz28

iTrader: (57)

One of my company trucks (4.8) did that exact thing and it was the knock sensors...

fst100

iTrader: (5)

may best replace/fix the codes associating with the emissions. may be in limp mode.

imma_stocker

iTrader: (19)

Manual or auto?

LS1 pwrd NOVA

iTrader: (2)

I wouldn't think the knock sensors would do that as all my truck throw that code and never an issue. Am I wrong, that's weird with knock sensors.
The codes are air, rear 02s etc... nothing of that should make it do what it's doing.
It's been 6 months since the header install with the same codes thrown after the headers were installed, so limp mode doesn't sound right.
It's a 60e auto, edited my og post.
Has a new racetronics fuel pump also installed 6 months ago.

imma_stocker

iTrader: (19)

Does it happen rolling into full throttle or just when you mash on it?

Any gauges to read what's physically going on with the car? (fuel pressure, diagnostic gauges, IAT, MAF, knock, etc)

LS1 pwrd NOVA

iTrader: (2)

To be honest I don't know as my son was driving. He probably mashed it.
I also put it in 1st gear and it did the same thing.

cookseyb

Limp home mode, Dealer can usually clear it and tell you the cause.

Kawabuggy

iTrader: (1)

"limp mode" as some of you guys are alluding to is 3rd gear only. It does not sound to me like this is the issue or there would be transmission codes present indicating why it went into "fail safe". If it is a "fail safe" issue there should be a p0700, and some other associated transmission codes. But, if it is going into failsafe-3rd gear which I guess is possible, it could be because of a loss of power to the trans. We have seen bad ignition switches drop power to the trans which makes the trans default to 3rd gear only. Also, if you truly think that the trans is defaulting to fail-safe/3rd gear only just hold the gas pedal & rpm's at a steady point and then pull the shifter down into the manual D2 position. If the trans is stuck in 3rd, it will downshift, and rpm's will rise when you move the shifter into the D2 position.

Me thinks more diagnostics are needed before doing anything else.

My personal recommendation-attach a fuel pressure gauge/tester to the fuel rail and then tape it to the windshield so that you can see the dial from inside the car. Now go out and drive it and see what the fuel pressure is doing when the problem occurs. If the pump is dropping out momentarily under heavy stress, it will cause the symptoms you describe. So will a plugged fuel filter. Please post back and let us know what you find out.

2000TransAm24

iTrader: (2)

My car developed severe hesitation issues when I installed long tube headers (cheap *** flowtechs huge mistake.) I remember the issues mostly occurring under part throttle though. Can't describe in exact detail since it's been many years. The only other time my car would not accelerate when going wot was when I made a mistake when tuning and the injectors would max out under wot. My car is also 4l60e.

RevGTO

iTrader: (12)

My car has gone into limp mode for various reasons over the years without throwing a code. But the basic test is valid. If the transmission is shifting through the gears, it is not in limp mode.

Fuel pump issue was also my first thought. My car drove fine around town, but I noticed it went extremely lean when I logged a run at the track. Instead of trying to read a fuel pressure gauge while going WOT on the street, I took it to a dyno shop and sure enough, fuel pressure starting dropping precipitously at about 4000 rpm.

Lastly, one other area of agreement: change the fuel filter before doing anything else. This is a neglected maintenance item on many f-bodies and in my experience they need to be changed at least every 15,000 miles.

DANOZ28

iTrader: (1)

not sure if this will help but after my heads cam intake install my car went into limp mode and it turned out to be a teeny tiny wire off the sensor on the back of the intake broke. goes from sensor to computer. worth a check.

LS1 pwrd NOVA

iTrader: (2)

Ok guys, still have this issue as it hasn't done it in a while as it's been cold outside.
Finally it started doing it again, it's getting warm/hot outside. You can't even drive it around normal without it fall8ng on its face.

<<Problem is we're losing fuel pressure when car acts up, drops to around 20 psi>>

We have a 255 racetronics in tank fuel pump, a hot wire kit and new fuel filter that's not even a year old. So do you think it's the fuel pump or internal regulator that's messing up when it gets warm outside.

imma_stocker

iTrader: (19)

Hate to say this.... pull the fuel pump basket out of the car to replace the $10 pre-pump sock filter and check EVERYTHING in the basket closely while you have it out and apart. Pre-sock filter shouldn't have to be replaced yet but its one of those things to replace anytime you have access.

Since the pump is fairly young it may have clogged the sock, wiring issue, kinked or leaking fuel line, loose hose clamp, dirty regulator, corrosion, or several other little headache type issues.

LS1 pwrd NOVA

iTrader: (2)

Looks like maybe it's the pump per racetronix and a few others.... dam

https://ls1tech.com/forums/fueling-i...m-outside.html