pontiackid Posted March 26, 2014 Report Share Posted March 26, 2014 alright so my 05 ss is stock other than the exhaust. it just flipped 80,000 miles. its throwing a po300 code and I cant figure it out. here is what started it and what happened. I was on the freeway almost home and the gas light flipped on. it started chugging and felt like I had to give it a lot more gas to keep my speed. I was nearly at my exit and I got off the freeway and got gas not even 5 miles after this started to occur. filled it up and it still is acting up. Here is what I did with parts I got from buddies that were good or stuff I had that was good and still got nothing swapped out all 8 coils with ls2 coils all new 8 plugs all 8 plug wires maf map sensor added some sea foam to the fuel I checked fuel pressure. priming it, its 55lbs.. driving it, its at 60lbs and stays I tried unplugging one injector at a time and I could hear a change in idle everytime. tapped on the cats with a hammer and sounded solid. I guess at this point im lost. I was told to try the fuel filter or fuel pressure regulator. but I know both are in the tank on a 05. but I have good pressure so how would that be? any help would be great. I never take my stuff in to the shop. but thinking I may have to at this point. Thanks! Quote Link to comment Share on other sites More sharing options...
JC03SS Posted March 26, 2014 Report Share Posted March 26, 2014 Maybe maf related or TB. Try cleaning both. Quote Link to comment Share on other sites More sharing options...
pontiackid Posted March 26, 2014 Author Report Share Posted March 26, 2014 Already tried a new maf. Guys are saying crank position sensor?? Quote Link to comment Share on other sites More sharing options...
avtonomb Posted March 26, 2014 Report Share Posted March 26, 2014 Did you try disconnecting the battery? Let it sit and reset the system. Maybe a glitch? Quote Link to comment Share on other sites More sharing options...
Blown 346 Posted March 26, 2014 Report Share Posted March 26, 2014 Normally a crank position sensor will cause the vehicle to wither shut off on its own, or not start. Your code is a random mis fire code which could be from the brand of plug you are using to the plug gap being incorrect, like said a bad MAF will normally be the issue with the plugs being used are the right ones, and thegap is correct. A crank sensor code issue doesnt come up with a Po300 code. There are multiple crank sensor codes and you dont fall into that category. Quote Link to comment Share on other sites More sharing options...
pontiackid Posted March 26, 2014 Author Report Share Posted March 26, 2014 I'll try the battery. I put ac Delco plugs In it. I changed nothing though in the first place then it happened. It's 3 weeks to get it In a shop on a scanner Quote Link to comment Share on other sites More sharing options...
Blown 346 Posted March 26, 2014 Report Share Posted March 26, 2014 What is your plug gap set to, and whats the part number on the plugs. Just because a parts store computer will say certain plugs will work with your vehicle they will not. For instance, The parts store computers tell me I can use Champion plugs, those are for chrysler products. By taking it to a shop they are going to do what you already did. pull the codes, and start what you are already doing, plus paying them to do the same thing. Quote Link to comment Share on other sites More sharing options...
pontiackid Posted March 26, 2014 Author Report Share Posted March 26, 2014 Alright guys. Pulled the exhaust off and ran it open manifolds. Runs perfect and all kinds of power. Either one of the cats or both were plugged not sure which Quote Link to comment Share on other sites More sharing options...
CJ_978 Posted March 27, 2014 Report Share Posted March 27, 2014 I threw a p0300 a few weeks ago my cats were clogged Quote Link to comment Share on other sites More sharing options...
abss_2003 Posted May 11, 2014 Report Share Posted May 11, 2014 I got this same problem yesterday drive home from work. I was doing 120km/h and the cel started flashing, didn't notice anything different, truck still ran good, no loss of power. After about 10sec the cel light stopped flashing and all was good. All the above checks other than cats have been done (cleaning and replacement of obvious parts) A lot of you guys are mentioning the cats being at fault, but isn't there an underlying problem to this? What's causing the cats to fail? Quote Link to comment Share on other sites More sharing options...
JC03SS Posted May 11, 2014 Report Share Posted May 11, 2014 The cats are honey comb looking inside after years of heat they start to come apart and clog. That's a lot of guys probs on here just think these cats are around 10 or more years old. Quote Link to comment Share on other sites More sharing options...
coal miner Posted May 11, 2014 Report Share Posted May 11, 2014 Cut them off . That's all there good for is to clog up. Quote Link to comment Share on other sites More sharing options...
abss_2003 Posted May 11, 2014 Report Share Posted May 11, 2014 I take it thou the guys with the bad cats were having drivability issues eg. rough idle, no start, no power ?I had no issues when the cel started flashing. I'm wondering if I should do a crankshaft variation relearn? the only reason I say that is my truck was in storage all winter long and the battery was dead for a while. Quote Link to comment Share on other sites More sharing options...
abss_2003 Posted May 11, 2014 Report Share Posted May 11, 2014 Cut them off . That's all there good for is to clog up. What do you do when the truck has to be tested for emissions? Quote Link to comment Share on other sites More sharing options...
Blown 346 Posted May 11, 2014 Report Share Posted May 11, 2014 You fail the emissions test.lol Quote Link to comment Share on other sites More sharing options...
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