so i driven down the highway and i'm tryin to pass this old ass man up so i can get off the highway. well at about 50mph the car starts shaking. i let off the gas to see if it will stop and it did. so i gave a gas again a lil and it accelerated fine. while all of this was going on my check engine light was flashing and stayed on. i erased the code and it came back up, and now its doing it a lot worse. like 35-45 when i give it gas hard. now i've owned the car for 2 years of that 2 years i had brand new motor installed. not jus new to me but brand new. when i bought the car the fuel gauge did not work, i was told that i would have to replace the fuel pump$500 at he dealer. well i still havent replaced the fuel pump and im starting to think that pump is starting to go out. if someone can help me out, i dont want to replace the pump yet cause i dont have to $200 to buy the pump and installing is not a problem i'll be doing that. gotta love the access panel in the back.

i've poured sum sea foam into the throttle to clean the injectors and it still does it.


i need help so i can unlock my new motor with less than 1k mi

sounds like a plug or wire. Not a fuel pump issue.

How old are wires? That would be the first thing I'd replace.

I had a cracked spark plug that worked fine except under medium load.

Just got the code for random misfire (P0300) on my way back from school.
While driving the trac off light kept turning on and off, but the car was acting fine. i turn into my neighborhood and the SES light starts flashing at me. I pulled it over and turned it off to prevent damage. The car was still running fine and never felt like it missed a beat. I limped it home with the SES light and trac light on (around the block). pulled in to check the codes and the only one that is relevant is p0300. (also a P0140 for not having a cat or rear O2)
I am about to pull the plugs and wires but they are literally only a few weeks old.
What else can cause the random misfires? I also have a new-ish LQ4 MAF sensor and N* TB with new sensors.
Cam sensor or crank sensor? wouldnt they also set a separate code?

Thanks,
Matthew

How many miles on the car??

150k, most stuff in it isnt that old.

I had random misfires, .
Replaced my wires first, no change....
a new set of 104's took care of it

front 104's still look new, and they should since they have 1,358 miles on them. wires were done at the same time and i used acdelco.
i'm about to pull the rear plugs as soon as the motor cools down some, but i dont expect to see anything wrong with them either.

what sensors can throw this code? anyone with a FSM?

I was getting this code while the lim gasket was bad. replaced today, code gone.

hmm, i know i've been loosing some coolant (a cup or 2 over a couple months) and it's about that time. any way to verify that is the cause?

The plugs are not white/ashy, burnt or wet.

i planned on doing the lim at the same time as the rockers, i may have to move that deadline up some...

You could have your oil analyzed. That would not confirm the cause of the misfire but could verify if the coolant that is disappearing is in the oil, or not.

http://www.blackstone-labs.com/
If you sent them a request for the kit it will arrive quickly and as soon as they get it back they will email the results. You could have the results back in a week or so from today.

Bert

I was able to actually hear the leak and hunt it down with a broom handle, though I know that's pretty shade-tree, and not the recommended course of action.

The job itself was about 6 hours for me, replacing valve cover gaskets, as well as lim sc and tb.

$100 for gaskets, FI O rings, EGR delete kit, and the lock tight.

i think it is leaking into the cylinders and burning off. i occasionally get white smoke on cold start ups.
i have been meaning to send out my oil (already got the kit from them), but havent had the extra $$.

james, where did you order the LIM from? i want the new aluminum one, but the one on rockauto doesnt specify material.