When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Have a 96 SE 5speed 158000+ miles. When driving in any gear the car sometimes lurches/jerks and I have to either go to neutral, release clutch and put back in gear to stop the jerking or take my foot off the accelerator for a few seconds then lightly push down again.
I removed the MAF housing and noticed the insulator duct was blocking part of the opening. I put it back to not block the opening and cleaned the MAF sensor. It ran fine for a couple of days but the problem has come back.
The car also sometimes revs while in idle, goes from 700rpm to either 1500 or 2000 for half a minute then back down but continues to do this.
Any thoughts what to check? Also, I still have the original clutch in the car, the car seems to pull fine but been so long that I may remember what a proper one feels like. I've had the car since 1999 bought from original owner.
I had a similar issue with a Mazda MX-6, and it was a crack in the rubber accordian-boot that connects the throttle body to the intake manifold. It usuallt happens in one of the folds, and when the engine rocks, the crack opens up and lets in "false/unmetered air", and the engine will buck. You can probably check this my running the car in neutral with emergency brake on, and either push on the accordian-boot/hose, and see if the engine bucks, or you can manually goose the throttle cable at the engine to make the engine rock, and see if it accelerates smoothly, or bucks.
I've had a number of 4th gens around that mileage need a good overall cleaning. If you intake tube doesn't have leaks from cracked rubber or a vacuum leak, its most likely time to give the IACV and EGV system a good cleaning. If this hasn't happened yet, I will be willing to bet they need a good cleaning. I had a failing EGR almost drive me crazy once because it caused a vacuum leak that resulted in bucking like you describe.
Checked the air duct hose (rubber accordian-boot) and it didn't have any cracks. I cleaned the IACV earlier this year but always good to recheck. The EGV will have to wait until next weekend when back from business trip. CEL came up after removing and reconnecting the air filter parts, shows P0120 which, correct me if I'm wrong, I think is the throttle/pedal position sensor switch and a P1447 for the EVAP.
These are beyond my skills but if someone can give instructions I can check.
I would suspect the MAF sensor first and perhaps the throttle position sensor second. I've got a 5 speed A32 Cefiro with the VQ20 (in New Zealand) and just had similar problems. Even though I've got the smaller engine almost all the other components are the same. My symptoms were idle hunting where the idle would drop from about 800 down to 500 every 20 seconds then recover, if I held the revs at 2000 it would drop to 1500 every 20seconds. It was driving me nuts trying to diagnose it. It was like this for about 2 months but then when the MAF died completely the car would buck and surge so bad it was practically undrivable and wouldn't let me rev past 2500 (in limp mode).
Once the MAF had died completely my mechanic was able to find the issue on a scan tool and he just so happened to have a car like mine to swap out the MAF to double check.
From what I understand the MAF sensors in these A32's can develop corrosion over time inside the MAF sensor internal wiring (not the part you can see) which sends the ECU a bad signal. At first the car will still run as the ECU will try to do the best with the signal it has, but eventually the MAF sensor will fail completely and the ECU will not be able to run the engine correctly. When the MAF is still in the process of failing it can cause the ECU to do all sorts of strange things, my car was idle hunting, surging, cylinders missing, and running rich, which made it hard to diagnose. Once I replaced the MAF sensor all that stopped and now the car is running better than ever because I pretty much replaced everything else to try and solve the problem!
Your issue may be something else, but because you said that your car temporarily improved after you cleaned the MAF sensor that would be the primary suspect in my opinion.
I would suspect the MAF sensor first and perhaps the throttle position sensor second. I've got a 5 speed A32 Cefiro with the VQ20 (in New Zealand) and just had similar problems. Even though I've got the smaller engine almost all the other components are the same. My symptoms were idle hunting where the idle would drop from about 800 down to 500 every 20 seconds then recover, if I held the revs at 2000 it would drop to 1500 every 20seconds. It was driving me nuts trying to diagnose it. It was like this for about 2 months but then when the MAF died completely the car would buck and surge so bad it was practically undrivable and wouldn't let me rev past 2500 (in limp mode).
Once the MAF had died completely my mechanic was able to find the issue on a scan tool and he just so happened to have a car like mine to swap out the MAF to double check.
From what I understand the MAF sensors in these A32's can develop corrosion over time inside the MAF sensor internal wiring (not the part you can see) which sends the ECU a bad signal. At first the car will still run as the ECU will try to do the best with the signal it has, but eventually the MAF sensor will fail completely and the ECU will not be able to run the engine correctly. When the MAF is still in the process of failing it can cause the ECU to do all sorts of strange things, my car was idle hunting, surging, cylinders missing, and running rich, which made it hard to diagnose. Once I replaced the MAF sensor all that stopped and now the car is running better than ever because I pretty much replaced everything else to try and solve the problem!
Your issue may be something else, but because you said that your car temporarily improved after you cleaned the MAF sensor that would be the primary suspect in my opinion.
Your theory makes sense.
The computer gathers data from the sensors, then makes decisions based on what it is told. It also monitor's the effects of its decisions.
A bad MAF might not trigger a code, but will send bad data to the computer. A cycling rpm might result. . ,
The computer gathers data from the sensors, then makes decisions based on what it is told. It also monitor's the effects of its decisions.
A bad MAF might not trigger a code, but will send bad data to the computer. A cycling rpm might result. . ,
Good to get some confirmation from a senior member, I'm still in the process of learning about the internal workings of the A32
In the end I got a second hand MAF for $160 which I was happy about just to get the car working again. I don't know what Nissan USA would charge for a new MAF, but Nissan NZ were going to sell me a new OEM maf sensor for $1000.00 which is absolutely outrageous.
Update. I checked the wire harness of the IACV to make sure it's getting power and also the resistance on the IACV. Both checked good. I also removed the IACV and checked that it is moving when turning the ignition. It's been fine since I did that except for a couple of times when I upshifted and it felt like I downshifted.
I ordered a new Delco AF10164 Air Flow Sensor that said it was an OEM replacement and installed it. The CEL turned off when I started the car but the idle started to going up and down again and when I tried to rev the engine it only went to 3000 rpm before it started "coughing". The car turned off moments later.
I put the original MAF back on and the car is working as before. Steady idle (if a bit over 650), revving over 3000, and no "coughing".
Any thoughts as to why the Delco unit would cause the issues I had?
