P0300. Needing some input.

[DanomiteSS]

I have a 99 ss camaro m6 with 47k miles. List of mods.
Hooker longtubes,
Hooker 3 in y
bbk intake
ported t.b
And a agr delete.

Car was running perfect for two months after installing all th new parts. Ran fine one day the next morning I fired it up and it threw a (low voltage input code for the tps) and a abs code for the traction control to be turned off. I'll look up the codes when I get done posting this. So I immediately went and bought a new tps. I've done everything I can think of. The car has a miss (or hiccup) under load and is random.
Here's the list of everything I've done to it.
Plugs, wires, tested all the coils with a new one. Fuel filter. Checked fuel pressure. Cleaned maf, cleaned the ground connections on the harness. Checked compression. Tested for 5 volt reference at the tps. I even took it to the dealership could only afford for them to diagnose it for an hour and the tech said when the misfire starts it's cylinder 7 but that's all he could figure out. So yesterday I figured I'd swap out the t.p.s with a new one for Shits and grins and it seemed like it was fixed. Soooo today I got on it to pass a dump truck on the highway and miss 4th like a rookie, after that the miss came back but worse. Got off the highway laid in to it through 1st and 2nd let off and the engine felt like I was running on 3 cylinders. After checking my scanner It was throwing the p0300 code. Got back in and nailed it because I was pissed and it went back to running with the random hiccup. Sorry for the long story but I NEED some professional input. Thanks in advance

[pajeff02]

Disconnect the wire harness connector to the MAF and see what it does. This will force the PCM into speed density mode so don't be getting nuts with the loud pedal. The disconnected MAF will set a code, but let's see what happens when you disconnect it.

[DanomiteSS]

Disconnect the wire harness connector to the MAF and see what it does. This will force the PCM into speed density mode so don't be getting nuts with the loud pedal. The disconnected MAF will set a code, but let's see what happens when you disconnect it.

Did that too.

[0rion]

any usual noises when the motor is at idle? Possibly bent a pushrod at some point missing a shift? You really need to get a scanner where you can see live data so you can definitely figure out what cylinders are missing. If it were just 7 the code would be p0307 so I suspect you have more than 1 missing. I would want to see what the fuel trims are saying and see what voltages you're getting from the O2's. If all that checked out I would start looking at injectors.

[pajeff02]

^^ This. A good scanner will allow you to see live engine data, including O2's and fuel trims. You can shoot a vid or take a pic of the screen and post it up on here for us to look at.

[DanomiteSS]

^^ This. A good scanner will allow you to see live engine data, including O2's and fuel trims. You can shoot a vid or take a pic of the screen and post it up on here for us to look at.

No it doesn't make any weird noises it doesn't even have the usual ls1 rattle at cold start. My scanner will read live data and the voltages on the 02's are good. When it was throwing the p0300 yesterday the stft's were both at -10.x. normally they will run between -3.x to 5.x. I'm posting from my phone so I can't attach pictures. Or at least I can't figure it out at the moment. But last night on my way home it seemed like it cleared up about ten miles from my house... Ive had one of my buddy's put it on his scanner that does a lot more than mine and he couldn't see anything wrong. His scanner wouldn't even pick up the miss. I could e mail you guys some freeze frames off my scanner if that would help.

[0rion]

can you view misfire counts per cylinder? If so you may have to drive around with the scanner a few times to get a picture of what cylinders are missing. A bent pushrod necessarily won't make a racket but just something to keep in the back of your mind as a possible culprit. I wouldn't go tearing into the motor to pull pushrods on a whim though. See if you can narrow it down to some cylinders and then start moving some injectors around. Another thing I just noticed is the BBK intake.....are you positive there's no leaks around that intake? Notorious for not sealing well. I would think your issues would be a little different if it were leaking but again....just something to rule out.

[DanomiteSS]

Actually I think I bent a push rod I uploaded a video to my Facebook. Add me and see what you think. Daniel sisson

[0rion]

I don't do facebook.....a bent pushrod will make a clicking sound though usually. If you've missed a shift there's a pretty good chance you bent one on the stock push rods. I would have to look but I'm pretty sure I have my stock set of pushrods in the shed I'll send you for free if you want them. If it were me though and as long as I was in there I would put hardened pushrods in there.

[DanomiteSS]

Ok update....... pulled the valve covers off and found no bent push Rods pulled the plugs all but TWO were fuel fouled. Ran the codes found a p0108 map sensor high input voltage. So I replaced the plugs and the map the noise is gone but it runs horrible and is still throwing the p0108. I think it's time to take the intake off and inspect the harness.

[SMWS6TA]

Also when you change out the TPS you need to do a relearn procedure.

Disconnect the TPS wire harness.
Turn key ON.
Turn key OFF.
Reconnect the wire harness.
Turn key ON and then open the throttle blade fully open then close.
Turn key OFF.
Start the to motor. You ECM should have reset the TPS parameters.

If those plugs are the only ones fuel foul, I would get them checked out. Your injectors might be going bad.

[DanomiteSS]

2,4,6,8,1,5 were fouled. It's no longer throwing the tps code but now it's also throwing p0500. I'm thinking it's in the harness or computer