# Nissan sentra P0303 code **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [May 7, 2013, 2:44am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165 "2013-05-07T02:44:48Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Kslice39](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@Kslice39](https://community.cartalk.com/u/Kslice39)\ **Post date:** [May 7, 2013, 2:44am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/1 "2013-05-07T02:44:48Z")
It keeps reading the code P0303 “cylinder 3 misfire”. All coil packs, fuel injectors, spark plugs have been replaced. The exhuast smells normal. The oil is the correct color(maple syrup color, NOT milky). It’s not blowing through coolant. Compression test came back normal. It’s not the cat converter because the exhaust doesn’t smell like rotten eggs. The car is sometimes hard to start. it hesitates/stumbles and shakes really bad. It feels like its not getting enough power. Anyone have any advice on what’s going on or what to do next? ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 7, 2013, 3:16am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/2 "2013-05-07T03:16:42Z")
Have someone check the Mass Air Flow sensor. I’ve had Nissans come in with misfire codes that were caused by a dirty/defective MAF sensor. Tester ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [May 7, 2013, 6:26am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/3 "2013-05-07T06:26:42Z")
@Kslice39 I would measure compression on all 4 cylinders. If #3 is considerably lower, you might need to adjust valves, or you might have worn rings. Let us know, please ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [May 7, 2013, 6:35am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/4 "2013-05-07T06:35:49Z")
@Kslice39 you don’t need to post 3 times (or more) to ask why you have a #3 misfire. Anyways . . . What are your compression readings? Dry and wet, please ---
**Author:** ![Kslice39](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@Kslice39](https://community.cartalk.com/u/Kslice39)\ **Post date:** [May 7, 2013, 7:37am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/5 "2013-05-07T07:37:35Z")
All 4 pressures were the same ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [May 7, 2013, 7:43am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/6 "2013-05-07T07:43:45Z")
@Kslice39 Nevertheless, can you post them, please? Have you verified that #3 spark plug is actually getting spark? Hook up a test plug to #3 plug wire and start car. Should have bright blue spark. Have you verified that #3 injector is actually working? ---
**Author:** ![Kslice39](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@Kslice39](https://community.cartalk.com/u/Kslice39)\ **Post date:** [May 7, 2013, 7:59am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/7 "2013-05-07T07:59:46Z")
I didn’t mean to post that many times. My computer froze when I hit the button, sorry. All the compression readings were the same. I don’t remember the exact number, I did the test a week ago. We took it all apart and the plugs were dry. We tried switching packs to see if it would say #2 or #4 would misfire but it still said #3. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [May 7, 2013, 8:14am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/8 "2013-05-07T08:14:30Z")
This site also becomes problematic at times so don’t worry about multiple posts. It’s been a bit goofy at times for me while kicking me off or freezing. If the compression readings are good (and offhand it sounds like they are) you might consider the possibility that the fuel injector on that cylinder is not pulsing. This could be done with a Noid light or by using a mechanic’s stethoscope or long screwdriver as a substitute to see if the injector is clicking as the engine is running. ---
**Author:** ![Kslice39](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@Kslice39](https://community.cartalk.com/u/Kslice39)\ **Post date:** [May 7, 2013, 8:21am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/9 "2013-05-07T08:21:24Z")
I will try that, but I just replaced the fuel injector yesterday. Shouldn’t it be working properly if its brand new? ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [May 7, 2013, 9:11am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/10 "2013-05-07T09:11:12Z")
@Ksliced39 The PCM provides ground to the injectors. If the injector driver is faulty, that new injector has no chance. ---
**Author:** ![Kslice39](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@Kslice39](https://community.cartalk.com/u/Kslice39)\ **Post date:** [May 7, 2013, 1:01am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/11 "2013-05-07T01:01:15Z")
Ok so first off I keep having P0303(cylinder3 misfire) come up. All spark plugs, coils, fuel injectors have all been replaced and its still throwing this code. I scanned it again this morning and this is what the code reader said(sorry it’s a lot): P0303 MIL on 3 INC Catlyst Evap 02 snsr 4 ready Misfire Fuel Comp 02 Htr It read these in this exact order. I have a CP9125 actron OBD2 PocketScan code reader if that helps anything. PLEASE someone help me out! I’m desperate and I’m so frustrated with this car. I’m not sure what else to do to get it running properly! ---
**Author:** ![Cirrus](https://avatars.discourse-cdn.com/v4/letter/c/a9a28c/32.png) [@Cirrus](https://community.cartalk.com/u/Cirrus)\ **Post date:** [September 29, 2020, 7:21pm UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/12 "2020-09-29T19:21:02Z")
I have the same issue I have literally replaced everything. I took it into a mechanic and he checked everything out he fixed a vacuum leak I had and determined I had a bad throttle body. Which I had suspected. So I replaced the throttle body and had it reprogrammed. But it’s still running a cylinder 3 misfire code. I even did the SES reset trick which lasted for a day then the code came back. ---
**Author:** ![Dappersworth](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dappersworth/32/22638_2.png) [@Dappersworth](https://community.cartalk.com/u/Dappersworth)\ **Post date:** [September 29, 2020, 7:53pm UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/13 "2020-09-29T19:53:48Z")
What are your long term fuel trims? ---
**Author:** ![Cirrus](https://avatars.discourse-cdn.com/v4/letter/c/a9a28c/32.png) [@Cirrus](https://community.cartalk.com/u/Cirrus)\ **Post date:** [September 29, 2020, 11:30pm UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/14 "2020-09-29T23:30:01Z")
Honestly I don’t know I don’t have a fancy enough scanner for that. ---
**Author:** ![Dappersworth](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dappersworth/32/22638_2.png) [@Dappersworth](https://community.cartalk.com/u/Dappersworth)\ **Post date:** [September 30, 2020, 4:23am UTC](https://community.cartalk.com/t/nissan-sentra-p0303-code/79165/15 "2020-09-30T04:23:26Z")
I have a 20$ bluetooth scanner, and I can read that data with Torque Lite