ls1 drivability issue.... need help

[LeonbergerG]

Got an '01 ws6 that in high rpm shifts from 1-2 and 2-3 throws a random cylinder miss fire code. Checked the fuel pressure going down the road but it stays around 60 -/+ 4#'s. Gauge bounces around erratically though. Does not hold pressure when key is turned off.

Just changed spark plugs, didn't change anything. Wires are good. Not sure if its coils or?????? Any ideas

[STEVE-O]

Only happens at high rpm? If so is check make sure your rockers and all is tight might be getting some valve float or slip

[LeonbergerG]

K. Doesn't do it all the time.

[Chadz89GTA]

Clean maf, have o2's checked etc etc a dirty maf will do strange things

[Rocky31186]

Are you tuned by chance? 100$ says if you have brian tune it, he will tell you whats wrong in a datalog..

[Chadz89GTA]

Are you tuned by chance? 100$ says if you have brian tune it, he will tell you whats wrong in a datalog..

 

+1

[LeonbergerG]

Honestly don't know..... just bought the car a couple months ago. Should get it checked.

[Rocky31186]

I would contact brian, and he will hook you up. He will also be able to tell you if your car has any type of tune on it...

[LeonbergerG]

I'm building an lq4 for the car soon. Hate to spend money on a tune now and then... drives ok just sluggish after a shift. Out only has 2 02 sensors also. I think it would have a tune.

[Cordell]

Scanning it would be the best place to start.

[Green Bastard]

when you turn the key off does the pressure drop quick? I'm thinkin it could possibly be a bad regulator and it could be running lean at high rpms.

[LeonbergerG]

when you turn the key off does the pressure drop quick? I'm thinkin it could possibly be a bad regulator and it could be running lean at high rpms.

 

This is kind of what I was leaning towards. It does drop pressure when the key is off . Also starts hard about every other time but if you cycle the key 2-3 times it starts right up

[AJ]

sounds like the pump isn't long for the world. you might also want to check the fuel filter to see its getting the volume through it that the engine needs.

[Drew2o2]

Sounds like its time to get a racetronix fuel pump kit with wiring harness. Regulator is a small possibility is it easy to start or does it crank for a while?

[LeonbergerG]

Cranks for awhile. It has an access panel cut already over the fuel pump...

[AJ]

Sounds like someone already put an aftermarket pump in and needs primed before starting.

[LeonbergerG]

Should it need primed? Thought out should hold pressure. Should I put a check valve in line?? Or just change pump. I'm getting ready to build a new motor, but wanted to spray this one but obviously not if it has an issue

[Cordell]

Should it need primed? Thought out should hold pressure. Should I put a check valve in line?? Or just change pump. I'm getting ready to build a new motor, but wanted to spray this one but obviously not if it has an issue

 

Depends on what they put in there. My car has a Ractronix pump and hotwire kit, and it doesn't need primed. I suppose if a cheap knock off pump was used it may have a bad check valve in it, if it even has one.

 

If you checked fuel pressure at WOT when you were having an issue and it only fluxuated by 4 psi or so, I'd be looking in to other things before I condemned the fuel pump for that issue. Your start-up may be related though. What are you trying to fix here?

[LeonbergerG]

The motor like it quits pulling at high rpm only after I shift though. Like shift at 6k and it doesn't pull hard into the next gear for a few seconds

[Cordell]

The motor like it quits pulling at high rpm only after I shift though. Like shift at 6k and it doesn't pull hard into the next gear for a few seconds

 

Interesting, as I said before I'd scan it and see what the computer has to say.

[LeonbergerG]

Wish i had a scanner

[Cordell]

Wish i had a scanner

 

I can scan it with EFIlive, what side of town are you on?

[LeonbergerG]

Thanks but not from town. In galion. Hour away from Columbus