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Discussion Starter · #1 ·
I resently picked up a 2002 2.5 Altima and it had a little bit of a ruff idle and wouldn't move in gear so I replaced the throttle body and did the relearn and both cam and crank sensors and the mass airflow sensor and fule pump and I'm still right where I started if I let the car sit for a while itll start and run somewhat normal but it still is verry jumpy and it seems that when the car gets warm it goes into limp mode and keeps wanting to spudder out and die and if I put it in any gear itll shake really hard and want to move but it's like theres no throttle response it doesnt rev up or move and if I let off the gas in gear itll shut off unless I disconnect the mass airflow sensor and itll let me drive it in limp mode I'm not sure where to go next with it any help would be appreciated thanks everyone.
 

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One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM from this web site: https://diyservicemanuals.com/. The section EC.PDF is the one you need to read.
 

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Discussion Starter · #4 ·
The cars hit or miss sometimes I can go start it and itll drive half a mile or so and itll go in limp mode and not move and sometimes I can start it and itll have no throttle response at all but the valve on the throttle body moves but when it does run it jumps and smoke like its getting to mutch gas and the load stays at 100% at all times
 

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The cars hit or miss sometimes I can go start it and itll drive half a mile or so and itll go in limp mode and not move and sometimes I can start it and itll have no throttle response at all but the valve on the throttle body moves but when it does run it jumps and smoke like its getting to mutch gas and the load stays at 100% at all times
First thing to check is your engine ground, since it only takes a few seconds. With the car running, put a voltmeter on the lowest scale and measure from the block to the negative battery post. It should read no more than 50 millivolts (0.05V).

A common problem with random engine shutdowns, difficult startups, rough running is a marginal camshaft position sensor (CMP) or a marginal crankshaft position sensor (CKP). Most of the time when this happens, the "check engine light" never comes on; subsequently when performing an ECU code readout, there was no fault code set. There's been many members here on the forum that have had problems similar to yours and the fix was replacing those two sensors.

The best and cheapest fix for this situation is to replace both sensors at the same time; the reason for doing this is there is no way to determine which sensor is at fault with this type of condition. You can take your vehicle to a dealer/repair shop and they'll tell you there is nothing wrong after they go through with diagnostic tests because at that time the vehicle was running OK. You could end up spending $200 or much more depending on how much time/parts are used.

When replacing sensors, always use Nissan OEM parts from a Nissan dealer; aftermarket electronic items generally are not reliable, don't last long, and many times are DOA. The sensors are not very expensive; around $120. Inspect the harness connectors on all the sensors for any oxidation or loose connections. Insure that any water resistant connector is in good condition; if the seals have been compromised, then any water intrusion can cause intermittent problems.
 

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I resently picked up a 2002 2.5 Altima and it had a little bit of a ruff idle and wouldn't move in gear so I replaced the throttle body and did the relearn and both cam and crank sensors and the mass airflow sensor and fule pump and I'm still right where I started if I let the car sit for a while itll start and run somewhat normal but it still is verry jumpy and it seems that when the car gets warm it goes into limp mode and keeps wanting to spudder out and die and if I put it in any gear itll shake really hard and want to move but it's like theres no throttle response it doesnt rev up or move and if I let off the gas in gear itll shut off unless I disconnect the mass airflow sensor and itll let me drive it in limp mode I'm not sure where to go next with it any help would be appreciated thanks everyone.
From the way you're describing the new MAF; when disconnecting it, you're at least able to drive it at low RPMs which seems to point to a problem with the new MAF or it's wiring. Consider re-installing the old MAF; but first clean it. Don't try to open the throttle plate by hand; you'll surly screw up the throttle motor.
 

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If it's getting 5v dont you think the circuit would be alright
You've got two other wires to check out; possible short or open condition. The point is - MAF unplugged, engine will run; MAF plugged, engine will not run. Follow the FSM to trouble shoot the condition. If continuity testing checks out OK, then the ECU may be bad; just a guess at this point.
 

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Do you know how to bench test the throtle body
You can download a copy of the FSM from this web site: https://diyservicemanuals.com/. The section EC.PDF is the one you need to use for testing the Electric Throttle Control Actuator which consists of throttle control motor, throttle position sensor that's part of the throttle body. If you have the throttle body sitting on a bench, you can perform resistance tests with a multimeter by using the diagnostic tests taken from the FSM.
 

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Discussion Starter · #19 ·
I found a ohms test for a gm throttle body that looked the same as the one on the Altima and it failed so I'm going to go to the junkyard to see if I can find another one
 

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Discussion Starter · #20 ·
I found a ohms test for a gm throttle body that looked the same as the one on the Altima and it failed so I'm going to go to the junkyard to see if I can find another one
 
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