02sslayer

iTrader: (4)

i have a 2002 ss. it has a cam and heads, bolt bons etc...i had the car tuned a year ago.

i installed a fast 90/90 a couple months ago and i havnt had it retuned yet. it was running fine up until about a month ago. now when i get it into the upper rpms it runs like dog doo and im getting the po300 code. so im thinkingn it needs new plugs and a tune. i could really use your guys opinions, i want to replace the right parts then first time so i dont waste any money. has anyone else had a situation like this? your guys help will be much appreciated, thank you.

02sslayer

iTrader: (4)

anybody?

tpcaz

I have 99 T/A with bolt ons and nitrous. Use HPTuners to monitor and tune. I started getting the same thing out of the blue and couldn't put my finger on it. But as I worked the issue, I discovered the code would show up at low RPMs, even idle, which ruled out many of the other obvious problem areas. An internet search revealed this code and problem occurs with many different manufacturers and was usually attributed to a bad crank sensor. Many people who had gone to reputable mechanics found the mechanics went for the plugs, coils, wires, etc. first, only to end up changing the crank sensor (after people spent hundreds of dollars for parts they didn't need). I used my HP Tuners to slightly desensitize the crank sensor and it took care of my issue. If it hadn't, I would have had to change it. From what I understand, it's not that hard to do or get to. Hope this helps.

99MUSTANG5.3L

Just had this p0300 on my 5.3,turned out to be low fuel pressure. Search p0300 in the pcm diagnostics section.

02sslayer

iTrader: (4)

Thanks for the posts guys, im hopin it isnt the fuel pump. I would hate to change out one of those *******. Im gonna look at the plugs first and see if thats the problem

smokinponcho73

iTrader: (6)

The fuel pump isn't that bad to replace. Just cut out above the tank.

TehGODofGreen

iTrader: (18)

I had that same code a year ago I installed spark plugs got to swoll with one and it split. From boot tip to the nut the car ran fine 30mph and less but hard acceleration and when it got up to thermostat temp it would sputter changed a lot of stuff thought it was fuel filter clog. Or bad pump, bad injector, crank sensor, maf and few other senso turned our to be a 6$ spark plug I over tightened. Not saying that this will fix your problem because 0300 is a bitch to find out what's causing it. But checking plugs free and easy.