I own a 2004 Chevy cavalier LS sport with the 2.2 ecotec engine. A few days ago it just started sputtering and running poorly so we got it to autozone and the scan came back with the codes P0201 and P0300. I looked up many options and started to install different parts to no avail. First I installed all new spark plugs (standard bosch platinum), that didnt help so I got the Ignition coil and the TPS and replaced those. The car still ran the same so I went to get the ICM and changed that. After all those new parts the car still ran the same and acted exactly the same. I decided to take all those parts back and buy 4 used fuel injectors and wiring harness (I took them off a 2004 cavalier w/ 2.2 engine at the junk yard) since one of the codes says that fuel injector #1 is bad. After installing those the car still doesnt run good so I had them re scan it at a mechanic shop and I got the same 2 codes as the original scan. On a side note I run premium gas and full synthetic oil and I usually fill up at the same place every time. Anyone got any ideas? and please dont say PCM
Well you could pick up a set of fuel injector test lights and see if it's actually firing. If you're motor is stock you don't need to be running premium fuel, it's not helping anything, that could be amplifying your issue. If you're not getting a fire signal at the injector, then it's time to look for shorts or opens in your wiring harness. Also, has the fuel filter been changed recently? That could cause misfires.
first off, stop throwing parts at it. If they read the codes, then the little receipt type paper they printed should tell you the codes symptoms, and any possible ways to diagnose/repair the issue.
a po201 is indeed a faulty injector code. but it is electrical.
the po300 is a random cylinder misfire. could be on any cylinder. Like Sparky up there said, try everything fuel related first, then try everything spark related. I would guess you probably have a bagillion miles on the fuel filter and spark plugs (the stock ones). REPLACE WITH IRIDIUM!
first and foremost, dont throw any more money at parts. try swapping one injector for another and see if the issue follows. pull your fuel rail, and place it over a bunch of rags (to be cleaned or disposed of properly) or into a bucket, pull ignition fuse and try to start the car. Of course it wont start, but this will let you see if the injectors are indeed injecting. if they are they reconnect all that. Replace spark plugs with proper IRIDIUM ones. Trace all wires to and from all fuel parts, and ignition parts, and see if anything is loose or broken.
Guys, I sold the car to Brandon earlier this year. The spark plugs were AC delco and had roughly 20,000 miles on them if I remember correctly when this issue started occurring. My thoughts are that if it were the fuel filter or fuel pump, the car would not run at all. Since the spark plugs, ICM, Injectors and Injector harness have all been changed and made no difference, it would seem that the issue may lie within the ECU, given that the injector issue is electrical related. Otherwise, it is possible that a ground has become loose or there is indeed a break in the wiring before the injector harness.
