was hopping I wasnt going to have to post one of these..

car is a 2002 SS with 46,000 on the clock.

Just recently pulled the heads to install a fresh set of LS7 lifters. Reinstalled heads with new GM gaskets and ARP head bolts. Final torque is 70ftlbs.

Installed a fresh Torquer V.2, Pacesetter LT's, and TSP y pipe. Also installed 2 new Bosch front O2's (Odd thing here is one pigtail is black and the other is RED...??? wtf.. same part number on the box though) Also installed fresh Tr55's gapped to 56 and new plug wires, and a new MAP sensor from advanced auto... no new intake gaskets.

Here's the problems: p0300 (and a flashing SES.....), y pipe is banging, no throttle response unless its floored (and then is makes DAMMMNNN good power), and when putting around, the motor seams hung at 1200-1500 rpm (even at like 15-35mph)... also getting NO MPG... used 3/4 of a tank to go 60 miles... car also has a 2600 stall and nelson tune for the above mod's...

I'm thinking a few things could be doing it. blown head gasket, leaking manifold (never really seamed to tighten down), wrong O2, banging y pipe...

also, both of my knock sensors are cracked (the porcolin on top)

yalls help is always preciated..

 

that code is for a random cylinder misfire! These could be your possible problems: * Faulty spark plugs or wires
* Faulty coil (pack) * Faulty oxygen sensor(s)
* Faulty fuel injector(s)
* Burned exhaust valve
* Faulty catalytic converter(s)
* Stuck/blocked EGR valve / passages
* Faulty camshaft position sensor
* Defective computer

probably your o2 sensor or or one of your injectors isn't seated properly which is causing it lo throw in to much fuel....look at those first.....check also and see if your gettting spark on all cylinders...it could be just dumping fuel in one or more cylinders and not burning it!

 

I did replace the cam sensor with a truck sensor (130K miles on it)

no cats, didnt think coils could just go out like that (but I'll check)

no egr... how do I test the injectors?

 

anyone else before I start pull the heads again?

 

you'll have to look along the fuel rail and see if they're all in properly...if they are you will have to check and see if your gettin spark on all cyliders.....it would help if you had a scan tool and you can look @ the PID's looking over the pulse width modulation of the injector duty cycle and see if they are all firing the proper amount of fuel

 

damn I need a friend with a modis or HP...

 

you would actually need an oscilloscope to check the sine waves of the injectors....i honestly think it is an injector issue...if your intake manifold is not all the way tight then your PCM also wouldn't see that the cylinders are getting enough fuel and is making them over work

 

you wont need to pull of the heads for this issue

 

Make sure none of the spark plug wires are touching the LT's, it'll arc and cause a misfire at low rpm's.

 

the plug boots are touching... could this cause it?

could a slight banging of the y pipe on the floorboard be causeing the random misfire this badly?

the light starts flashing AFTER I get on the gas slightly (as in rolling into the throttle after coasting) I can feel it pulling timing.

 

bump for the day crew..

 

One of my plug boots is against a header and kinda melted and it causes no issues.

 

Why such a big gap on the plugs? I was thinking something along the lines of .45.

Also definitely need to get it tuned.

 

Bad knock sensors or a bad knock sensor harness will cause missing and bucking. Pull the intake and replace the broken sensors, and put some new intake gaskets while you have it off.

 

That's alot piled up that'll make it difficult to find just one issue. Do the maintenance stuff first (broken sensors, possible mis-matched O2 sensors, etc). I'd expect you to get a lean code if the intake weren't sealed to the heads on one or both banks. Once the sensors are replaced and all reading correctly, then start into finding the P0300 code. If the PCM has not been tuned, it is not unusual for it to throw that code due to the aftermarket camshaft and erratic (relative to stock) idle.

 

I can tell you that I had big issues with Y banging; the car was almost stalling when it was hitting the floor when going WOT. Get it soldered nicely and this issue will disapear.

About the wires, if theyre MSD, theyre really hard to pop on the spark plugs and theyre easy to melt on the headers(I hated them but its just my 02.). I witch back to GM LS6 wires and it was night and day difference. The car had no torque at all when a wire was half melted..

Check if theres no melted wires touching headers somewhere, it could cause shortcircuit and burn the fuse that is controlling the MAF(happened to me,the car was dying,running like crap and getting worst mpg).

just some thoughts..

DONT PULL THE HEADS AGAIN!!!!!!!!!!!!

 

its tuned by nelson performance.

 

bad o2 sensor mine did the same exact thing.