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Need some help with this one. I have a 2000 vert with a constant P0300 code after a few minutes at idle following some preventative maintenance. Mind you, the car ran perfectly well prior to replacing the oil pressure sensor, the camshaft position sensor, cleaned the TB and installed new intake manifold gaskets. After putting it all back together, the car runs rough and throws a P0300 code.
I double-checked all the electrical connections and vacuum lines and did not find any breaks or leaks. Thinking the new camshaft sensor maybe DOA, I reinstalled the original sensor but still get the P0300 code. Maybe there’s a hidden vacuum leak on the PCV system or a faulty MAP sensor on the rear of the intake manifold. I did not check the coil packs or spark plugs/wires since they were not replaced but should I?
Any suggestions on what’s causing the misfiring and error code?
Then the clamping force is way off. The blue loctite specifically called out on the service manual acts as lubricant for the fastener, so you have a fraction of the clamping force applied for the design intent. Even more of a concern with brand new gaskets. I would start there.
Also, if you are asking for help and someone on the form time time to ask questions............take time to answer them.
Save yourself time and money...take your car to a professional diagnostician if you can find one...you don't have the equipment or knowledge to fix this.
Thanks the for the advice and appreciate your help. The manifold bolts did not have any evidence of loctite on them when I removed them, but that makes sense now.
As far as the gaskets; they are aftermarket (not GM) so I will change them to OEM gaskets.
Thanks again for the guidance.
All I was asking for was some help from those who know more than I do on what to look for and not to be reminded that I don’t have the “equipment or knowledge” to diagnose a problem.
Honestly I did not think I would need to be a ASE certified mechanic or have $30,000 in tools to change out a few parts on a 26 year old car, but obviously I was wrong. I know these cars can be temperamental, but had no idea how much so kindly cut ne some slack, please.
Honestly I did not think I would need to be a ASE certified mechanic or have $30,000 in tools to change out a few parts on a 26 year old car.......
To be fair.....you don't. What you do need is a factory service manual for your year car, and the aptitude/ability to understand the content and understand schematics. You don't need $30k in tools, but you do need the right tools. A baseline for troubleshooting tools.... like a spark tester, vacuum gauge, fuel pressure gauge, test light, DMM, and a scanner capable of reading live data. Keep in mind this is a C5 forum, addressing issues specific to a C5...........not a "how to work on cars forum".
I agree with the advice about finding someone that has the ability to perform diagnostics. Most good shops have thousands invested in their equipment to do just that.
What you are describing sounds exactly like a vehicle I had that needed a throttle body re-learn after some minor work was performed.
Unfortunately you are back to getting someone with diagnostic equipment to find out for sure.
My own P0300 story - with the Vortec engine in my RV (Chevy Express 3500 cutaway circa 2005). Started easy and seemed to run OK on the highway even though HP Tuners was reading misfires across all 8 cylinders. Took it to the shop and they said plugs and wires looked OK - in their words "The engine bay is in good shape and has not been messed with much" (only 55k on the clock). They then fitted a new crank sensor and while doing this found that one if the wires on the connector was burned! They installed a new sensor and wiring harness "and did a relearn procedure" and said the codes are gone. I'm on a trip with it now and will recheck when I get back.
Not sure if LS1 requires a "relearn procedure" but might be worth looking into
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P0300 code after replacing parts
