will the front 02 sensors cause code p0300??

[rispoli_23]

please help guys i have tried everything my tuner is looking at it again but he thinks its something else besides the tune

thanks
richard

 

[patman0911]

Probably not just a random misfire code without causing other, more visible symptoms like fouled or burned plugs from running rich or lean all the time.

What year and model and how many miles? What mods?

Still have cats and rear O2s or were they turned off in the tune?

When did it start misfiring - did it coincide with the new tune or any other modification?

Is it a bad misfire or can you not feel it?

What all have you tried so far?

 

[rispoli_23]

thanks for the reply ... no its not real bad i believe i can fell it shutter a lil at idle and sometimes it dies or wants to die when i come to a stop, yes the code came ob after about 3 days after my new tune along with p0602,
i put a new iac valve on it and looked any vac leaks i cleaned my maf sensor i have new plugs but have not put them in yet,

99 gt
80,000 miles

cms stage 1 cams
75 acufab tb
c&l plenum
typhoon intake manifold ... wich i dont like
o/r h pipe with flows ... the rear 02 sensors are supposed to be turned off
sct x3 tuner
jlt short ram intake

i did get these codes before and i got a mail order tune from brookspeed tuning and it did make them go away but my exhaust smelled really stong my new dyno tuner said my car was running lean thats why it smelled so bad si he retuned it , it ran great for about 3 days then the light came on and it has been running like crap ever since and its been 3 weeks and he still hasnt got to me yet but he keeps telling me there must be something wrong causing the p0300 code .... i dont know what to do

 

[rispoli_23]

another thing i wish somebody could help me with is ever since i have had my cams i have fought and fought with my car .... when i come to a stop or push the clutch in the car always acts like its gonna die the rpms will drop really low and then they will pop back up .. it is so annoying and it sounds like crap because it always seems like my car is going to die ... i have put 3 iac valves on it in 2 years because the techs at my work always say thats whats causing it ... i do notice if i squeeze the hose between the iac valve and the pcv valve it wil die or almost die ... but i dont know im consued i just want my car to run and sound good .. ay suggestions on how to fix this problem

 

[wmburns]

Check EGR system

Check your EGR system. Note, excessive EGR flow will also cause idle problems.

P0300 - Random Misfire

The random misfire DTC indicates multiple cylinders are misfiring or the PCM cannot identify which cylinder is misfiring.

• Camshaft position sensor (CMP)
• Low fuel: less than 1/8 tank
• Stuck open EGR valve
• Blocked EGR passages

One or more EGR passages may be blocked or partially blocked. If this is the case the Misfire Detection Monitor will indicate the EGR port to check for possible blockage.

 

[rispoli_23]

how do i check the egr system for blockage?? i did read to put a vac hose on it and suck and if the car stumbles then the egr system is working so i done it and when i suck on the hose it does stumble and try to die ... and how can i check the cam shaft sensor i there 2 ... thanks for the help

 

[rispoli_23]

will the crank shaft bolt cause this problem too

 

[wmburns]

how do i check the egr system for blockage?? i did read to put a vac hose on it and suck and if the car stumbles then the egr system is working so i done it and when i suck on the hose it does stumble and try to die ... and how can i check the cam shaft sensor i there 2 ... thanks for the help

Disasemble the throttle body and clean the EGR passage ways.

For a high mileage car, consider replacing the EGR valve itself.

Spary carb and choke cleaner backwards down the EGR line.

Inspect the vacuum lines to/from the DPFE sensor. On older high mileage cars, these lines are bad about drying out and cracking/leaking.

Yes, a loose crank shaft damper CAN cause random misfires.

 

[rispoli_23]

where and what is the dpfe sensor ?? what does it do ??? and yes all those hoses back ther look dried out ill check them for leaks tonight thanks u ...

 

[fast97gt]

its the aluminum rectangular peice about 3 inchs behind the egr valve.