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Rick, Nissan Master Technician
Category: Nissan
Satisfied Customers: 503
Experience:  27 Years working in Nissan Dealerships Currently working for Nissan Dealer
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Pick up: hey, how are you? i have a 1995 nissan pick up truck

Customer Question

hey, how are you?
i have a 1995 nissan pick up truck 2wd 4 cal automatic,idle goes up and down at 2000rpms
i had the code #43 for the throttleposition sensor, i replaced it and did not fix it.
do i need to reset the sensor? or what do i do?
Submitted: 1 year ago.
Category: Nissan
Expert:  Mike V. replied 1 year ago.
Hi there,I would check for a possible vacuum leak. Take some carb cleaner, and with the truck running, spray the hoses and the steel lines under the intake manifold. If the idle smooths out or increases then you have a vacuum leak that needs to be resolve. Check the vacuum line to the egr closely as well. This one tends to crack.If they all prove good, then next, turn the truck off and unplug the mass air flow sensor on the throttle. Start it and see if the idle speed smooths out. If it does, then the maf is the likely culprit.Please let me know what more I can do to help.What happens next:Just Answer will now charge you for the full amount of your question.My goal is to provide you with 5-star service. If you cannot rate me at least 3-5 stars, we will keep working on this.Just Answer does not compensate me for my time and effort; you do with a 3-5 star rating.Follow up questions are included in your question price even after rating.
Customer: replied 1 year ago.
so, i used the carb cleaner and nothing happened
unplug the maf sensor and the engine had a hard time idling only at 3000 rpm but not the same way as with maf sensor on.
is there any other way to test the maf sensor just to make sure is working right before i spend over $200 on this sensor.
Expert:  Mike V. replied 1 year ago.
HERE is a link to the flow chart for testing the maf. The truck won't run right with it unplugged, and will not go past 3k rpms as the computer will turn off the fuel supply, this is why we test at idle with it unplugged for improvement.Please let me know what more I can do to assist from here.Also, please be sure to rate my answer, I really would appreciate it.
Customer: replied 1 year ago.
hello, sorry for the late respond, but i had to buy the maf sensor online and it took some time to get here, i put the new sensor on and nothing has change.
so what is the next step? or next place i have to look?
now i have to see if i can return the maf sensor
Expert:  Mike V. replied 1 year ago.
I apologize that the maf sensor didn't resolve it. Since I sent the link for testing I assumed you would replace it if it tested bad, but would come back to me if it tested good.Sometimes there are issues with the egr ports on the intake getting carboned up. You can remove the plugs on each section of the intake and make sure it's clean, if it's plugged up it may give you this issue.
Customer: replied 1 year ago.
i could not open the link for the maf sensor, so i just went a got one,
i'll check the the egr ports now, i'll let you know how it goes!
Expert:  Mike V. replied 1 year ago.
Sounds good, and if you have any issues with my links in the future, let me know! I will figure something out and sometimes the site is buggy when it comes to those types of things.
Customer: replied 1 year ago.
so, i check hoses and intake plugs, they all seem good, i did not see anything bad or dirt, i took the truck for a little spin around the property and the check engine light came on, it has the 41,43,and 12 codes!
any ideas?
Expert:  Mike V. replied 1 year ago.
12 is for the maf sensor. This might have been stored when I had you unplug the sensor.43 we know already is the TPSthe 41 is for the intake air temp sensor. Very common issue with these is a broken wire right at the IAT sensor connector. If I remember right its the yellow wire that normally breaks. There are updated parts from the dealer with a little longer wire so you can actually remove the air cleaner lid without breaking the wire. I could see this causing some surging because it doens't know the temp of the air.
Customer: replied 1 year ago.
someone told me about the wite on the IAT sensor but nothing is broken allready check that!
the tps sensor was replaced before i got the truck, do you think that could be the problem? may be it needs to be reset? or adjusted?
Customer: replied 1 year ago.
so? what is next?
Expert:  Mike V. replied 1 year ago.
If you have a meter you can attempt at adjusting the TPSf throttle position sensor is replaced or removed, it is necessary to install it in the proper position, by following the procedure as shown below:Install throttle position sensor body in throttle body. Do not tighten bolts.Connect throttle position sensor harness connector.Start engine and warm it up sufficiently.Measure output voltage of throttle position sensor using voltmeter.Adjust by rotating throttle position sensor body so that output voltage is 0.4 to O.6V.Tighten mounting bolts.Disconnect throttle position sensor harness connector for a few seconds and then reconnect it.
Customer: replied 1 year ago.
ok, i did the adjustment on the fps and nothing change, i still have the same problem, the is a taping/knocking sound coming from the top of the engine, you think that has something to do with it, the noise keeps getting louder with time, then i did a compression test and cylinder 1,2 and 4, had 130 psi while cylinder 3 had only 100 psi. what should i do next?
should i do a fuel pressure test too?
Expert:  Mike V. replied 1 year ago.
I am going to have to open this back up for the other experts. At this point sorry to say I am out of ideas.Please don't reply to me or they won't be able to see it and help out.
Expert:  Rick replied 1 year ago.
Hi my name is***** will try to help you with the issue your having with your truck. One thing that is critical with replacing the tps sensor is the engine must be running hot enough and it is common for the thermostat in these engines to be running a little cold and what that does is make it so the throttle body linkage doesn't make it all the way down to the hot idle position because the wax pellet that controls it isn't hot enough, so when you go to replace the throttle sensor your setting it up with the linkage in the wrong position and a lot of times its close to the closed throttle position and the ecm sees it as just off idle and causes the engine to surge at idle, I would make sure the engine is running a normal operating temperature 180-195 degrees before adjusting the tps
Customer: replied 1 year ago.
hi, sorry it tookso long for me to answer, i was on vacacion for a couple of weeks,
i reset the tps again , over and over and nothing has change!
still does the same problem at 2000 rpm!