In an attempt to be as detailed and thorough as I could be in order to correctly and potentially definitively diagnose the issue(s) plaguing the vehicle in question, this post is very long.

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Specifications

• Vehicle: 1998 Nissan Sentra GXE
• Engine: 1.6L GA16DE, 4-cylinder
• Transmission: RL4F03A, automatic
• Mileage: Approximately 222,000

Note: This vehicle is not equipped with a tachometer.

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The Symptoms

Hard/No (Re)start

When attempting to start the vehicle (cranking), the vehicle is hard to start. This used to be occur some months ago. However, in the past, it would start well when cold and would have trouble when warm/hot. Nowadays, it has trouble starting whether it is cold or hot. Also, if the vehicle has been recently driving for a period exceeding approximately ten minutes and/or it has been restarted quickly after a drive ten minutes in duration or less, it may not start at all unless given a few minutes of cooling down (and my repeated attempts to get going). I want to stress that it has trouble starting at all times now, cold or hot engine.

While attempting to crank at any period (that is, whether it is a time where it’s having more trouble or less trouble), it feels as though I’m bouncing up and down in the driver’s seat. Overall, the car just feels as though it’s going everywhere.

Regardless of the two previous issues occurring, if/when the vehicle does start, it sounds as though it’s almost dead and struggles to pick up to its normal idle (which probably isn’t correct to begin with).

Finally, there is an issue with starting the vehicle normally. That is, turning the ignition to START, hearing the starter, hearing the engine fire up, and then letting off the key. In my situation, 95% of the time the car will not start unless I let off the key. Once the key returns to the ON position, it will try to start up and struggle as depicted in the paragraph directly preceding this one.

Jerky Acceleration

This issue used to occur after about twenty (20) minutes on the freeway. It was extremely jarring, to say the least. Nowadays, it happens at around the same time, but I only do city driving to account for this issue creeping up in the hopes that I’ll be able to more safely pull over should the need arise.

This problem is extremely hard for me to describe in a manner that truly conveys how it feels/is. Once I reach the elapsed time roughly required for this issue to arise (which I generally try to avoid as much as possible), I will step on the accelerator and the car will seemingly jerk forward and backward. At this time, pressing on the accelerator will have seemingly no effect, save for very, very slowly increasing speed. Needless to say, having this occur is not fun and crossing an intersection while it occurs is difficult.

When this issue first cropped up, it only happened at highway speeds, most notably when I would have to really hit the accelerator to get on a badly-positioned on-ramp on my typical route. However, this now happens on city streets, as well, at very low speeds and when hardly accelerating.

Intermittent Stalling

Once the car has been driven for a period exceeding approximately twenty (20) minutes or multiple trips in a short period of time equaling or exceeding such a duration, the car may stall. It is uncertain what brings this issue about, other than that it will not occur if the car is driven a very short distance for a short amount of time (that is, time not exceeding the previously stated restriction).

When the vehicle has stalled in this manner, it has always been either when stopped or coming to a stop. Restarting the vehicle after this stall is extremely difficult. Sometimes it will restart after a few attempts and sometimes it requires many attempts and a possible period to cool down.

Clunk Into Reverse

When shifting to reverse, the car will clunk. It will feel like the whole car just got hit or it feel as though it fell in the same manner that you feel when you unknowingly walk off a curb only to hit the ground unexpectedly.

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The Tests

In order to provide some hard data for those attempting to help diagnose any issue(s), I conducted some simple tests using a digital multimeter. Due to time, knowledge, and ability constraints, these tests are not as exhaustive nor complete as they should be. Either way, hopefully this data can be used to help pinpoint any problem or rule out certain components and/or segments. Without further ado.

Throttle Position Sensor

1. Terminal 1 to Ground
   • Ignition “OFF”: 0.00 mV
   • Ignition “ON”: 5.23 V (expected: approximately 5 V)
2. Terminal 3 to Ground
   • Ignition “OFF”: 0.9 Ohms (expected: continuity should exist)

3. Terminal 2 to Terminal 3

   • Fully closed: 0.6 to 1.0 Ohms
   • Partially open: No change

   • Fully open: No change

     Note: This was a tight fit for connecting to the sensor itself with no visibility. I don’t think I did it correctly, so these values are probably off.

4. Terminal 2 to Ground (backprobe using paperclip)

   • Ignition “ON”

     • Fully closed: 0.643 V (expected: 0.35 – 0.65 V)

     • Fully open: 4.1 V (expected: approximately 4 V)

       Note: Voltage appeared to rise and fall smoothly according to reading on multimeter as viewed through the front windshield while I slowly pressed the accelerator down and then slowly released it.

Mass Airflow Sensor

1. Terminal 3 to Ground
   • Ignition “ON”: 12.06 V (expected: battery voltage)

2. Terminal 1 to Ground (backprobe using paperclip)

   • Ignition “OFF”: 0.00 mV
   • Ignition “ON”: 0.56 V (expected: less than 1 V)
   • Idle (warm-up condition): 1.224 V (expected: 1.0 – 1.7 V)

   • 2,5000 rpm (warm-up condition): Within range (expected: 1.7 – 2.1 V)

     Note: Voltage increase and decrease appeared to be smooth as viewed by multimeter.

Crankshaft Position Sensor

1. Terminal 2 to Ground (backprobe using paperclip)
   • Ignition “OFF”: 0.8 Ohms (expected: continuity should exist)
2. Visual inspection of component
   • Sensor did not appear to have any chipping
3. Terminal 1 to Terminal 2 (component)
   • 192.7 Ohms (expected: 166.5 – 203.5 Ohms)
4. Connector cleanliness
   • Appeared to be oil pooling in sensor connector, electrical contact cleaner was used until no more oil visibly remained

Idle Air Control Valve

1. Terminal 3 to Ground
   • Ignition “ON”: 12.41 V (expected: battery voltage)

Fuel Pressure

1. Ignition “ON”
   • 43 psi (expected: 43 psi)
2. Engine running, vacuum connected
   • 36 psi (expected: 34 psi)
3. Ignition “OFF” after previously being “ON” or engine running
   • Drops by about 2 psi immediately
   • Drops by about 5 psi after a period of five (5) minutes
   • Pinching supply line at this time causes pressure to increase by 3 – 5 psi, releasing pinched supply line causes pressure to revert to value held previous to pinching

Battery

1. Ignition “ON”
   • 12.4 V

2. Engine running

   • 13.5 V

     Note: I had been cycling the key on and off and leaving it on here and there while I conducted other tests prior to conducting this test. As such, the battery may have been drained somewhat by the time I got to this test. Weeks ago, I had gotten a value of a little over 14 V when testing this. However, there was quirk I noticed. It began increasing in voltage when the engine was running. Once it reached about 13.60 V, it began to struggle to increase. It would oscillate between 13.60 V and 13.61 V. After about ten seconds, it would rest at 13.61 V for a few seconds. Then, it would oscillate between 13.61 V and 13.62 V. It continued this process for some time until I got tired of watching it do this at around 13.70 V.

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Procedures Performed

Fuel Filter

Per a recommendation on a forum (etcg, to be specific), I replaced the fuel filter when I first posted somewhere attempting to solve my issues. The fuel filter in the vehicle was replaced with WIX #33023 on August 25, 2016 at approximately 221,000 miles.

Cleaning

Months ago, I had cleaned the Mass Airflow Sensor (using CRC’s MAF Sensor Cleaner) and the side of the throttle plate facing the MAF (I was lazy to take everything apart).

Recently, when performing the tests for which the values are presented in a previous section, I cleaned the Idle Air Control Valve and removed more of the throttle body to clean it more (however, I did not remove it completely as I was a bit lost on how to remove the accelerator cable). Further, as noted previously, I cleaned out some pooled oil on the crankshaft position sensor connector harness using CRC Quick Dry Electronic Cleaner.

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Additional Information

DTC Code(s)

There are not DTC codes present nor have there been when any of these issues have occurred. A cheap OBDII reader doesn’t pull any and putting the ECM into Diagnostic Mode II provides, by MIL flashing, 0505. 0505, in this manner, is Nissan’s code for no malfunction.

Air Intake Hose

The hose that connects the MAF to the throttle body is cracked about half an inch after the MAF. I attempted to look for another one online, but the dealer has discontinued the part and various other sides list it as available, but it is not. For now, I have cleaned the surface and applied duct tape as well as I could.

Transmission

A couple months ago, I checked the ATF. It was very low. I simply refilled it with the appropriate ATF. I did not flush and refill. I have not noticed any pooling of liquid below the vehicle at any point in time.

Valve Cover Gasket

A while back, the valve cover gasket was leaking oil everywhere. The problem had been fixed months ago and spark plugs were replaced at the same time. Misfires has been occurring regularly and did not occur, to my knowledge, after this was fixed. However, a bit of oil is leaking out again, though nowhere near what it was like before.

Miscellaneous

As for checking my timing, I have no tachometer. Without a tachometer, I cannot determine if the idle is correct and cannot adjust the idle screw. Without the idle being set correctly, the timing adjustment would be for naught. Additionally, I have a timing light, but cannot figure out how to do it as I can never see the timing marks.