I have a 1997 Chevy Monte Carlo with 49,000 miles in it. The engine is the 3.1 V-6. I keep getting the Service Engine Soon code of PO301, misfire on cylinder 1. I do not see any coolant leaks, nor has my coolant level dropped. The car idles smoothly. I have reset the SES light, but returns shortly thereafter. I have done nothing so far.
Does anyone know where I should start. Plugs, wires, O2 sensor, injector, coil pack?????
Please help. The vehicle has to pass emissions or the state will suspend the registration. (Milwaukee, Wiscosnin).
Please help.....Thanks...
Gus

change the plugs and wires first. It's a normal maintenance thing and won't be wasted money. you can test if the plug is the misfire if you have a timing light. Hook the timing light up to the cylinder that's misfiring, and watch the pattern of light flashing. It should be a steady, consistant flash. Any gaps would indicate a plug misfire. If the plug fires good, then you have a bad injector in that cylinder.

change the plugs and wires first. It's a normal maintenance thing and won't be wasted money. you can test if the plug is the misfire if you have a timing light. Hook the timing light up to the cylinder that's misfiring, and watch the pattern of light flashing. It should be a steady, consistant flash. Any gaps would indicate a plug misfire. If the plug fires good, then you have a bad injector in that cylinder.
I reset the code in the ECM, changed the plugs and wires, and drove the vehicle. After 10 minutes on the road, at 50 mph, the SES light came on again. No hesitation, rough driving or vibration felt. I did the timing light test on each new plug wire and all appeared to fire without an interruption. Should I change the injector next or the coil for the #1 cylinder?

i have the same exact monte as you and i had the same problem. what you are gonna have to do is change all of the injectors. if you change only one you are gonna have to go back in a couple of weeks and change another one bacause they all go bad after one starts messing up. i tried changing one ijector but it only was running good for a few weeks. jsut change all of them and you are not gonna heve anymore problems with it. the 3.1 L engine fuel injectors are known to mess up faster then what they are supposed to.

i have the same exact monte as you and i had the same problem. what you are gonna have to do is change all of the injectors. if you change only one you are gonna have to go back in a couple of weeks and change another one bacause they all go bad after one starts messing up. i tried changing one ijector but it only was running good for a few weeks. jsut change all of them and you are not gonna heve anymore problems with it. the 3.1 L engine fuel injectors are known to mess up faster then what they are supposed to.
I was afraid of that. Should I buy brand new injectors or refurbished ones?

I had the code of PO301, cylinder 1 misfire, on my 1997 Monte Carlo 3.1. I replaced all six fuel injectors myself, and the car runs great now. Just like it did when it was new. I live in Milwaukee, WI, where there is a big controversy of whether or not the fuel supply is poor. I no longer have the code in the car's computer. It was about a 5 hour job. I used reconditioned injectors.

New injectors, plugs and wires. Passed emissions.

good to hear it's fixed. Hard to believe they went bad in 49,000 miles, it's also amazing that a 97 only has that amount of miles. I thought my 96 was low with 72,000 miles. Luckily, My injectors have not had problems yet. (I live in Hudson, WI, on MN/WI border). There is no fuel controversy here.