Infiniti G20 won't run above 2000 rpm


#1

Infinity G20 (1992 high mileage) runs find so long as tachometer stays below 2000 rpm. Trying to determine if it’s worth it to get the problem fixed (funds are limited). The car stalls out – maybe too much fuel, or not enough fuel, or the wrong mixture. There appear to be two throttle cables under the hood. Guessing it has something to do with the second throttle. I know nothing!!! about cars.


#2

Possible plugged or collapsed exaust system (catalyic converter) one cable is throttle the other is cruise control or so I think


#3

Have the air and fuel filters ever been changed?


#4

It sounds like either something is impeding the systems’ abilities to breath (like a plugged exhaust or air filter) or something is limiting the fuel supply, perhaps a plugged up fuel filter, a weak fuel pump, a bad fuel regulator, or (a) bad injector(s) (I don’t know if this is Throttle Body Injected or Multiport).

If you truely know nothing about cars it might be a good idea to get it to a shop. If you open up a pressurized fuel line to attach a pressure gage you just might spray yourself with gas and go up in flames. I hate it when we lose visitors that way.


#5

Don’t worry - I’ll probably try the air filter first, then see if I can figure out how hard it is to replace the fuel filter.

Don’t know any history - recently obtained the car for free. Funds are limited. Suggestions should be least cost first. Thanks.


#6

“I know nothing!!! about cars.”

Based on that statement, I STRONGLY urge you to follow Mountainbike’s sage advice, and allow someone with some experience under the hood to replace your fuel filter. Whether you want to consider the possibility of being sprayed in the face with gasoline or whether you consider the cost of stripping a fitting, a DIY job could wind up being very costly for a neophyte.


#7

Don’t know if this will help you narrow it down. The car will run above 2000 rpm until the car is warmed up. In other words, when I first get in the car I can go above 2000 rpm without any problems. Also, I’m not sure if the car stalls out, but it definitely backfires.


#8

Yeah, that might help.

When the engine is cold a few things happen that are different from when the engine is warmed. One is that the computer bypasses the oxygen sensor (this being a 1992 you probably only have one) to allow the engine to run rich. The other is that a valve/shroud arrangement over the exhaust manifold diverts warm air from around the manifold to the engine intake to allow the engine to warm up faster.

Let me posit a few theories. First, it’s possible that the oxygen sensor (bypassed when the engine is cold) is throwing a bad signal and causing the engine to run too lean, not get enough gas to go fast.

It’s also possible that you have a critter nest (or something) in your intake snorkle that, when the “help the engine warm up” valve is closed is restricting your air intake.

Alright, the second theory is a “stretch”, but it’s free to check.