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Ron, ASE Certified Technician
Category: Nissan
Satisfied Customers: 33023
Experience:  34 years of automotive Repair
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1986 nissan d21 z24I jerks at 2750 rpm. What will cause

Customer Question

1986 nissan d21 z24I jerks at 2750 rpm.
What will cause this?
Submitted: 1 month ago.
Category: Nissan
Expert:  Ron replied 1 month ago.

Hello. My name is ***** ***** I am happy to assist you today. Give me just a moment to review your post, and I'll be right back with the help you need.

Expert:  Ron replied 1 month ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here. Jesting can be caused by an engine misfire , have you scanned the computer system to see if there are any fault code setting and if so what are they. I would also check the condition of the spark plugs and the wires as well. Post back with the scan results and we can work from there.

Customer: replied 1 month ago.
When it began jerking I began throwing money at it.
I replaced the rotor, cap, plugs, wires, fuel filter on fender and replaced MAF sensor. It began running like a motor boat, as well. Took it to Nissan to be checked out. The motor boat issue was a blown head gasket. Had it replaced and milled head. Fired it up and idled smooth but still jerked at 2750rpm.
Removed the muffler. Still jerked. Removed the catalytic converter and it still jerked.
Friends think it is the throttle position sensor and others the fuel pump.
Truck ran great one minute and then started it up and it was a different story.
Expert:  Ron replied 1 month ago.

Have you check to see if there are any fault codes setting as well as checked the fuel pressure while the problem is occurring?

Customer: replied 1 month ago.
I assumed(oh well) that when I took it to Nissan they would have run a diagnostic. As for fuel pressure while running, I am uncertain how to do that.
I had thought about blowing back through the fuel line to see if there was an obstruction.
What gets me is that Nissan forums have indicated many having the same problem but never posted a cause or correction.
This is a nice solid truck with a nice smooth ride, otherwise. It has 205K miles on it with an engine overhaul at 200K.
Expert:  Ron replied 1 month ago.

To run a fuel pressure test you would need to tie into the fuel supply line downstream of the fuel pressure regulator. Normal fuel pressure on the 1986 at idle should hold at least 36 PSI.

Customer: replied 1 month ago.
It idles and runs smooth and then at 2750rpm it all turns ugly. I will try and see if it is a fuel delivery issue. I think there is a predicted on the pump and possibly anothee filter just off the tank. I did change the filter in the engine compartment and it appeared clear.
I will stay in touch.
Expert:  Ron replied 1 month ago.

Okay let me know and we can work from there if need be.

Customer: replied 19 days ago.
I changed out the TPS without change. A friend had made the change and it fixed the problem.
Expert:  Ron replied 19 days ago.

Glad to hear you got it resolve and thank you as well.

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