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Just started to troubleshoot, but need any advice that may help. I have a SE 3.8L with 225k on it. I have a crank, but no start. I pulled up 2 codes P0140, downstream O2, and P0300, random misfire. Car ran fine, than the next day would not start. I have 50 psi fuel pressure and getting spark on all 6. I tried disconnecting the maf and cam sensors, but that did not work.. Pulled 1 plug, soaked with fuel. I replaced the crank sensor 3 yrs ago with an ac delco one. Replaced plugs and wires last year. also recently replaced the ICM after that failed last year. will keep at it, but any recommendations as trying to get it back to my son who is waiting? thanks

update on my no start- I pulled all the plugs for a compression test and all soaked with fuel. The compression test showed all cylinders ok. Decided to put new plugs since they were fuel soaked and the car started right up. It ran fine and restarted ok. Not sure of the cause of fuel/flooded condition. When it first happen, I told my son to floor the pedal to clear it, but that did not work. After towing it home, multiple tests with cranking of course dumped more fuel in it. So air drying the cylinders and new ac plugs (the old plugs only had 15 k on them) worked. I will keep an eye on the amount of cranking to start and look again at the fuel pressure regulator and maybe leaking injectors. Alot of good checks on those on this forum and you tube. So for now, it works, but hope to find the cause before it happens again.

after 1 week of driving and testing nothing found. the car starts up hot and cold fine all week. I tested the fuel regulator and injectors for leaks and all ok. Car runs fine except for hard acceleration- going up a hill, flooring it from a stop, hard acceleration on the highway- it stumbles, hesitates, rpm jumps around, and does not accelerate. This is new as before the no start it did not do this. If I accelerate smoothly, it runs fine. I changed the coils this week and disconnected the maf, egr valves to test if they were causing it. TPS tests ok. Cat was changed out 2 yrs ago. I have no codes. Vacuum is ok and no signs of broken valve springs. could the ICM do this? I am not getting any p0300 misfire, so thinking if it was misfiring it would throw a code. Any ideas or things to test? I am not getting fuel, air, spark, or exhaust needed when hard acceleration. any help would be appreciated.

Since this new issue started after changing the spark plugs, recheck the wires and firing order. Maybe you accidentally switched plug wires.

I double checked, all plug wires are ok, I had everything marked, i am thinking exhaust restriction, will perform a back pressure test soon. I just tested the maf and cleaned it. also vacuum gauge exhaust test showed ok. Magnaflow cat is only 1.5 years old.

I suppose that the cat could have been affected by raw fuel being dumped into it. Something you may want to check, if you have a fuel pressure tester with a long enough hose, try taping that to the windshield to see if strange things happen to the pressure when the problems show up.

nice thought, I will try, but yesterday the engine light finally came on after 2 weeks and 250 miles, I have the 420 cat code and checked the donwstream sensor signal, it does move from 0.2 to 0.5, so that might back it up. I will try the exhaust back pressure test soon and if that confirms it, I will replace the cat. It is a magnaflow with 27k on it. I tried yesterday full throttle when cold/first start. It does not have the problem during full engine cold, only when I get to normal temp. So maybe when the cat gets hot it restricts?

I think that likely would be the case. Sometimes, they'll become red hot.

Backpressure and vacuum test showed no exhaust restriction. When this started a few weeks ago, I suspected a bad coil. Once hot, I heard they can give trouble. I had one original ac delco and 2 cheaper ones I put on the last few years. So I replaced all 3 with Delphi good quality made in the usa $30 ea from amazon. When I installed, 1 was bad right out of the box, so I kept the 2 new ones with the old one and returned the bad one for credit. Then a few weeks of this problem (when hot, hard accel or up a hill, rpms jumped and lost power, no misfire code, but had the p0420 and more recently p 0404 egr). Me and a friend went back to the coil thought, so I put one of the cheaper ones I removed back on, and all is well, problem solved. It was the original coil that was not firing right when hot at certain high loads/acceleration. Not happy with a bad one from Delphi that sent me down the wrong path. I should have bought used ones from the junkyard or new AC Delco. All is well now, but learned some more on all the tests I did and the signs of a bad coil when hot.

Thank you for reporting back.