Expedition XLT 1998 4x4 won't go over 60mph highway

Maintenance/Repairs
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1

Not sure if it’s transmission issues, on the road it took me to a neighbor city with no issues, but on my way back, while running it went from 70mph to 57-60mph and it won’t let me go faster, it will not rev up more than 2000rpms, if i step further on the gas it will struggle to rev up, it will, but speed won’t go faster, engine just had been rebuilt, it has no catalyc converters. I live in mexico, instead it has 2 “silencers” which were just installed as well since it was making a lot of noise through the exhaust.

Been driving it in the city, (no more than 35mph) with no problems at all, all gears feel great, but haven’t tried to go up to 60mph again.

Here in mexico it’s hard to trust mechanics, I wouln’t like to get ripped off with the whole transmission, as I mentiones, I just rebuilt most of the engine, rings, gaskets, etc. and it wasn’t exactly cheap. Thanks in advance

2

Yikes. So many questions. Why was it rebuilt? How many miles?

3

It’s either running out of fuel (fuel pump dying), air (induction system ok?), the timing has slipped, or the MAF, MAP, O2, or one of the other sensors has crapped out.

I light of the vehicle’s age, I’d start by testing the fuel pump.

4

Yes so many question, new to forums, and new to car talk, thank you for the fast response, engine was rebuilt because water got to the engine’s heads thru a seal located in the timing chains section, (sorry if not using the right english terms, trying to translate from spanish mechanic).

its 188k miles and never been rebuilt before

I will check the gas filters, its the expedition I always wanted it but got it on poor conditions, I really will like to “rebuilt” it all as time goes by.

Will sure check on them sensors, also, here in Mexico gas it’s…uhm…really bad quality, I live right at the border with arizona, so I will try the arizona gas and see if it’s related.

5

Perhaps the best place to start would be with a repair manual from a parts store or the internet.

6

Thank you very much!

7

With crappy gas it could be just a clogged fuel filter.

8

…it will not rev up more than 2000rpms, if i step further on the gas it will struggle to rev up, it will, but speed won’t go faster…

It sounds like you may have several issues there, involving both the motor and transmission (or maybe the clutch if it’s a manual).

9

Sounds like the ideal car for Robert Gift.

10

I went to an autozone in town, computer popped out p0171 and p0174.

11

Check the fuel pressure at the rail. It will likely be low when trying to accelerate if not all the time. Change fuel filter first and try it you may be fine after that but if not check fuel pressure. Good luck.

12

P0171 - Fuel Trim System Lean Bank 1
P0174 - Fuel Trim System Lean Bank 2

13

Yes, bought fuel filter, I’m going to have it changed as soon as possible, so, basically that can trigger the fact that expedition won’t go faster? Does this mean transmission is ok? I had a chat with previous owner, he says he intalled a chinese fuel pump a couple of years ago.

14

“he intalled a chinese fuel pump a couple of years ago”

That’s already overdue to fail.

15

Should I replace the fuel pump as well?

16

You should TEST the fuel pump. You should only replace it if it’s bad.