My Engine is Misfiring?

has it been missing every since the cracked radiator was replaced? or is this a new problem? how long has it been since the radiator replacement and when the misfire started happening? this guide can help us fix it:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.

It started missing the night before I got the radiator put in.

ok,the only way to be sure is to have a leak down test or combustion gas test performed to verify whether or not you have a heat gasket issue.that is where you need to start before you waste any money on the car.does the car have good heat? if so does is suddenly go cold sometimes? any white smoke? or antifreeze smell?

ok I will definitely do that...The heat is okay it doesn't get hot like most cars but it gets pretty warm. it doesn't suddenly go cold and sometimes I see smoke come from under the hood when I'm driving it long distance or when I'm getting off the highway.

yeah,i would definitely get the leak down/combustion gases test done.if that is negative,which is a good thing then I would have it pressure tested one more time. I hope I have been of some help to you and please let me know how it works out.have a great day.

Thank you so much it was a bad injector#3 I got a new one the car runs great!

you are welcome.

I am having quite a few problems with my Altima. I think I will start from the beginning. The problems starting happening when the car was hard to start. It wouldn't crank unless you was pumping the gas pedal. The SES light was on. At that time, it was pulling the codes for the crankshaft positioning sensor, O2 Sensors, engine too lean, and speed sensors. I had all of them replaced. A few days later my SES light came back on. Around this same time, I begin getting a******** sensation when I'm driving and let off the gas pedal. I took the car to AutoZone and they scanned the codes again and now its pulling the codes P1574 Speed Sensor, P0128 Temp Sensor, and P0171 Engine to lean bank 1. I would like to know hwat could be causing the******** sensation that I am having, and what are the conquences of driving a car that has a lean running engine. Also, I forgot to mention, when I press the gas while the car is idling, it feels like something other than smoke is being pushed out the tailpipe. When I look behind the car, there is a black liquid coming out of the tailpipe. It is cold these days so I dont run the AC so im sure it cant be water. PLease help me with this issue. Thanks.

first of all, what are the odds that all those sensors failed at the same time?? nill. codes never identify bad parts, just failed systems.

the crank sensor is a common failure and there is a tsb on it from nissan. there is an updated flash as well for this issue which would solve most of your problems.
the 171 code is not an o2 sensor, it most likely is a vacuum leak somewhere and can be verified by a smoke test on the intake system.

I would have a shop check this for you as throwing parts at it has not fixed your car. The repairs will probably be narrowed around 1 system.

Roy

Ok thanks. But what could result in driving the car while it stating that it is in a lean running situation? The shop and everything that I need to fix the problem, as well as the Nissan dealership, is in the next city over about a good 35 miles away. I don't want to put further harm on the engine if any from driving it lean.

After replacement of the sensors, were the trouble codes erased?


Lean running conditions for one bank cna mean a skipped cam timing or clogged fuel rail, vacuum lekages and many more.

Clear the codes and run engine before rechecking the codes again and see which comes up first.

I have erased the trouble codes several times after the sensor replacement. But when I turn my car on and let it idle, the SES light comes back on giving me the codes for a speed sensor (which was replaced) and a temp sensor ( this code is new). Then after a few hours of driving the car, the engine too lean bank 1 code shows up again.

What were the EXACT trouble codes retrieved?

Have a compression test performed to see if they are within specs.

P1574, P0128, P0171 are the trouble codes. Also, just starting today, when the car was idling, the rpms got down to about 500 then eventually acted like it wanted to shut off, but didnt. When i shifted to reverse with my foot on the brake, the rpms got even lower to about 250ish and the engine started knocking but didn't cut off, but the car drives normal except for the******** I get when I let off the gas pedal.

Let start with the P1574 and P0128 since they are the ones that came on first.

DTC P1574: ASCD VEHICLE SPEED SENSOR

Description

ECM receives vehicle speed signals via 2 different lines, and detects vehicle speed for ASCD control. Vehicle speed signals are input from instrument cluster and Transmission Control Module (TCM) separately. Signal from TCM is via CAN communication line.

Possible Causes

Malfunction is detected when ECM detects a difference in values between the 2 vehicle speed signals. Possible causes are:


CAN communication line open or shorted.

Instrument cluster circuit open or shorted.

Defective instrument cluster.

Defective vehicle speed sensor.

Defective TCM.

Defective ECM.

DTC Confirmation Test

Start engine. Ensure TCS is turned off. Select DATA MONITOR mode with scan tool. Drive vehicle at more than 25 MPH. If 1st trip DTC is detected, go to DIAGNOSTIC PROCEDURE. If 1st trip DTC is not detected, system is okay at this time.

Diagnostic Procedure

1. Check for A/T system DTCs. If problem is found, diagnose A/T system. If problem is not found, go to next step.

2. Check VSS, VSS circuit and instrument cluster. Repair as necessary.


DTC P0128: THERMOSTAT FUNCTION

Possible Causes

Malfunction is detected when engine coolant temperature has not risen enough to open thermostat even though engine has run long enough. Possible causes are:

Thermostat stuck open.

Leakage from sealing portion of thermostat.

Defective ECT sensor.

DTC Confirmation Test

1. Replace thermostat with an OEM replacement. Turn ignition on. Select COOLAN TEMP/S in DATA MONITOR mode with scan tool. If COOLAN
TEMP/S is less than 140°F (60°C), go to next step. If COOLAN TEMP/S is not less than 140°F (60°C), allow engine to cool.

2. Drive vehicle at a speed of 50-75 MPH for 10 consecutive minutes. If 1st trip DTC is detected, go to DIAGNOSTIC PROCEDURE. If 1st trip DTC is not detected, system is okay at this time.

Diagnostic Procedure

Remove ECT sensor, and place in heated water. Measure resistance between sensor terminals, with water at specified temperatures.
See ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE table. If resistance is as specified, test is omplete.
If resistance is not as specified, replace ECT sensor.

the engine stalls at low speeds. Sometimes you feel a miss in the engine while running at faster speeds. It makes no difference if the A/C is on. There is no engine light comming on. Can you help?

Is the "Check Engine" light on? If so, take it to someone that can read the codes....then go from there...Mine had like 4 or 5 codes stored, "multi-cylinder misfire" was a couple, then a few they could'nt identify. Raised the hood, and I could hear a pronounced vacuum leak, but all hoses connected and in good condition. Kind tech at the dealership told me exactly what was wrong...Intake gasket blown, very common problem. Bought new gasket, took 4 days to repair in my driveway...No problems since....now 165,000 miles perfect....

I just had the speed sensor replaced a week ago. The thermostat code is a new one though. The main thing I am concerned about is all the problems and symptoms that my car is experiencing and the lean running condition it is in. I'm pretty sure a speed sensor nor a thermostat would make my car behave in such a way.

Please take not that the speed sensor code does not necessarily mean a bad speed sensor. It could be the wirings and other components as stated in the diagnostic information.

The ECT can cause lean running conditions if it is telling the engine conflicting information as compared with others.

Lean running running conditions can be due to vacuum leakages, slipped cam-timng etc. Have you checked those yet?

I haven't been able to have them checked at this moment for other reasons, but I really need to use my car so I need to know what problems could occur when driving my car when it's running lean. I was told by two technicians that it wouldn't affect anything major, but I have read online that driving lean will melt the internal engine components. I don't know which to go buy. What's your opinion on that?

When the CEL comes on, the lean running condition would be compensated by the ECM so there is actually no real harm to the engine.

Even with all the******** and rough idling its doing? It drive's fine, just that it idling rough and the******** i get when i let of the gas pedal.

If you haqve not cleaned the throttle body and IAC, get them cleaned and retest. Sometime poor idling would cause a lean condition.

Engine has number one cylinder misfire, bad shake. trouble codes showing are po 301, 180, 1464, and a few others. I have narrowed it down to the number one cylinder fuel injector wiring. No click or strong click from injector, but i have switched known good injectors and still missfires. all the injectors show approx, 8.7 ohms of resistance. i have replaced the connector, no luck. the wiring has 12+ volts on the supply side and 12+ volts on the signal side, while the others show minimal voltage on the signal side with key on. Could this be a possible short? checked all wiring from injector to computer, it looks fine I ran a continuity test on the number one harness wires which show continuity. Could it be shorting from one of the bad sensors? I am stumped. any ideas? Thanks

You need to be using a noid light for this test as to not harm the computer and get an accurate test of whether the signal is arriving or not. If you can confirm this injector is not getting a signal, you might try locating that wire at the PCM and maybe cutting it off to test if you have a good signal coming out of the computer. If you do, then try cutting that wire off at the injector plug and splicing in an overlay wire to see if that resolves the issue. If so, you can clean it up to make it a more permanent repair.

Hi, thanks for the prompt reply. I was thinking of doing something along that line. I actually took that wire off at the harness and did a continuity check at the computer harness, but i believe i was getting a continuity bleep on two wires. What is suppose to be the voltage or signal strength coming off of that computer signal wire terminal? Would any other codes have anything to do with this issue? Such as fuel temperature sensor? Thanks again for your help.

The computer sends out a pulsing ground signal to operate the injector. You cannot check continuity because that will not tell you if it is shorted. You are better off to cut it off at both ends before doing any testing. The grounding transistor in the computer are very sensitive so you have to be careful not to send any voltage down that line. This is why your testing needs to be done with a noid light or lab scope.

Hi, I cutoff the original signal wire at the PCM and at the harness. No difference. Injector is still not firing. I checked the voltage off of the cut wire and it is still producing 12 Volts at the computer terminal and at the harness with the spliced wire. All the other injectors have no real voltage present off the signal wire with the ignition on. I sure hope it is not the PCM. Any thoughts? Thanks again, Mike

Could be. You are going to need some in depth diagnostics to get to the bottom of this. I would look over the harness very carefully for any burnt or pinched spots.

I have replaced the connector with others twice already. Is that correct that I should not have any voltage on that signal wire? If I check it directly off the computer terminal and it reads twelve volts would that not mean an internal computer problem?

You should only see voltage if it is plugged into the injector and the key is on. You will read the power supply through the injector. That should go away with the injector unplugged.

I am reading twelve volts when the signal wire is not connected to the injector. I am even reading twelve volts off the ECM terminal with the wiring harness disconnected. I guess I have to bite the bullet and take it into the shop.

It sounds like you have an injector driver inside the PCM that has one bad, so the computer will need to be replaced.

Please let us know what you find so it will help others.

Best, Ken

Hi guys. Thanks for all your help. I believe I have found the problem. I noticed a little rust at the bottom case of the ECM where it sits on the console floor near the fire wall. I decided to open up the ecu case and found corrosion on the circuit board. One terminal for sure was almost eaten away. I cleaned it up with a soft brush and tried to re-solder it. I will put it all together and try and fire it up tomorrow My fingers are crossed.

Great work! please let us know how it goes.

Best, Ken

Hi Guys, well, bad news i fired it up today with the reworked computer still has the miss and all the codes. I guess the PCM was too far gone. I will try and look for a used one from the wrecker. Will that work as long as the tag matches? i guess i will have to take it to the dealership to have it flashed.

Yes, it sounds like the water damage got it. Try for a used one if not it is off to the dealer for a new one.

Thanks for all your help guys, much appreciated. Great site with fast responses awesome! Mike

Please use 2CarPros anytime, we are here to help and tell a friend.

Best, Ken