Well, at least you found something wrong. Hope clean injectors solve the problem.

Update: So it isnt the fuel injectors. now all mechanical things check out... next is electrical and the computer... Im getting a new computer from the junk yard this weekend hopefully Monday the truck is fixed.... 8 days in the shop including today...

I agree with trying a compression and leak down test. It's easy and quick to do and it will tell you the condition of your engine. If you can't do it yourself, it should cost about $60 to have it done.

UPDATE

Just got the truck back and list of thing. It runs great now!!

Oxygen sensor on catalytic converter replaced
Throttle position sensor replaced (main issue in my opinion)
Distributor cap
Spark plug wires
Cleaned all fuel injectors

In the end the TPS was the main issue because the truck was fine at idle and full throttle but did not have mid range which is why i had no power when maintaining speed because it was trying to just idle...

I changed the spark plug wires the day i brought it in but he showed me the ones i bought from AUTOZONE were damaged and were arching as well... So i got to take those back.

Im happy i now got it working. it was a bummer that it was in the shop for 12 days but the guy took care of me and the price could have been a lot higher then what i expected.

For guys in CT i suggest talking to John at CARS in cromwell he is good guy and keeps you updated with progress. John checked EVERYTHING on the truck, all the vacuum hoses, sensors, timing... everything. Him and his crew did a great job and im really happy. Tell him i suggested you.
http://www.carsllc.com/

Good to hear it is fixed!

Worse case scenario you just had a full tune-up PLUS done!

Glad you got it figured out, man.

I finally got my Silverado back inline, too. It's funny how easily the money falls out of your wallet when your rig has to stay at a shop for an extended time. Electrical/sensor problems stink.

Good to hear its back running well. It may not have been cheap, but it could have been a lot worse.

k_enn

Glad the issue is sorted out Romeo. I might just have to visit John... my emissions issues have been a lingering a long time & the shop (Modern Tire on Rt.15) I've been using has not been able to fix it yet.

Good to hear you found the problem!

Yeah def go talk to him, he is a small mom and pop shop so i would rather give him the work then a dealer.

Ok now im back to square 1... Im having issues again... See below breakdown that im debating to give to Nissan and bring it to the dealer and have them work on the truck.

If anyone has any suggestions i should have Nissan look at please let me know.


Symptoms:

1) Shifting from 2nd to 3rd gear - seems to go to neutral to long and then shifts up.
1a. Has been observed for a week shifting correctly until check engine light appeared. After check engine light was reset the transmission went back to shifting incorrectly.
1b. Shifting issue was not a problem until throttle position sensor was replaced. May be an electrical or computer mapping issue.
1c. Truck was brought to transmission shop, transmission appears to be in good condition for age. May be electrical sensor issue.

2) Loss of power
2a. stand still has no power to start going. If the pedal is floored the car does not go.
2b. Has trouble maintaining 65 mph on highway

3) Cold morning starts almost stalls out. Has stalled out completely once. Appears fuel air mixture is incorrect.


Possible fixes:
1. remap transmission control module
2. Computer remap for new throttle position sensor to fix shifting and loss of power.


Recent Maintenance To Date:
1. Throttle position sensor replace
2. Oxygen sensor in exhaust manifold replace
3. spark plugs and wires replaced
4. Transmission fluid and filter replaced
5. Fuel filter replace
6. Air filter replace
7. cleaned and flushed fuel injectors.

Here's a little info on our truck. We went to VT about a month ago, and was having trouble accelerating uphill on the highway. Since then, I replaced the throttle position sensor and fuel pressure regulator. I first did the TPS, and didn't adjust it properly. The truck would almost stall at warm startup, and wouldn't shift right (long neutral like you said). After adjusting it per manual (feeler gauges and ecu learn), it starts and shifts better, and seems to accelerate better.

I can't say if the FPR actually changed anything. It might be worth checking your pressure; I just replaced it as it was ~$45 for the part and $10 for the intake manifold collector gasket.

I still have a check engine light for very small evap leak (0456). Still tracking that down.

When you replaced the TPS, did you adjust and learn the ecu properly?

To be honest i don't know how to adjust the ECU. That is why im thinking i need Nissan to do it unless there is instructions in the manual? ill check that out later.

There are instructions in the service manual. Summary:

All performed while engine is at normal operating temperature!

TPS should be adjusted so pins 5 and 6 (top 2, marked inside connector) create a closed circuit with a 0.3mm feeler gauge installed, and open with a 0.4mm feeler gauge installed. I had .012 and .016 feelers respectively. This takes patience, and constant measurements.

After the sensor is adjusted and engine still at normal temp (not running), turn key to position 2 (run) for 5 seconds, then return to off for 5 seconds. Repeat this 20 times.

After I did those steps, the shifting improved and it felt like it ran better. I'm sure it affects fuel mapping, not sure about timing.

ok ill try it out thanks