Rpms drops to 1500 1400 after hitting 40 mph

20

Asked by FourtwentyOIL710 Aug 20, 2018 at 04:48 PM about the 1998 Lincoln Navigator

Question type: Maintenance & Repair

Very Low gas mileage and  rpms drops to 1400 or
800 to 1000 when not accelerating after reaching
40 mph. It catches speed but the rpms hesitate to
go up it mostly drops after 40 mph

19 Answers

This may just be the transmission up shifting. If you put your foot down the transmission should down shift and the speed pick up. In top gear your SUV's engine should only turn about 1,500 rpm at 60 mph. My Fords only turn 2,000 rpm at 70 mph.

1 people found this helpful.
20

It reaches 2000 rpms at first if i press the avveleration it goes up to 3000 but other than that i havent drove it past 50 mph.

1 people found this helpful.

Maybe the fuel level sending gauge is off. You need to have someone that knows cars drive it.

20

Before i would get at least a quarter of the gauge up with 25 or 30$ now it stays the same whether i refuel or not. its only sometimes that the gauge goes up but it still goes to low fuel either immediately or after about a block or 2 away it lowers.

20

I think it might have to do with the idle contol valve i just dont wanna mess with it since i have no clue on what to do.

20

And im sure i have dirty or clogged fuel injectors or a bad fuel pump. but a bad fuel pump would cause starting problems wont it?

20

It does idle pretty smoothly and no check engine light i do have a slight crack on radiator idk if that could be the cause but why isnt the Check engine light on

If the engine idles smoothly and the idle speed is steady at 750 rpm your idle control valve is good. I would fix the radiator leak before you over heat your engine.

20

Yea i know. So the only question i have is why does the car hesitate or drops rpms after hitting 40 mph could it be a fuel problem?

20

Also the thermostat gauge is not functioning. For this reason i only drive short distances so far ive been told that it doesnt seem to overheat. A few months back i had all the coolant release due to a torn hose and it had overheated then. i know its not overheating because the check engine light would start blinking like it did on the highway a while ago. These problem barely started about 4 or 5 days ago.

You really need to have a mechanic check your car out. Maybe it just needs a tuneup and filter change. A good fuel system cleaner might be a good idea.

20

Cool thanks for ur help and the quick reply bro it really got some stress out my head. Im hoping it has nothing to do with the tranny

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