No acceleration at full throttle?

[1993gen1eh]

Hey guys, just joined here. I have a problem with my explorer, hopefully someone knows what’s up. When I bought my explorer earlier this year, it ran and drove perfectly. After a while of driving it, the trans started to slip. I checked the fluid and it was low so I added some and it fixed it. Now, today about 1 month later, I am driving down the road and suddenly it won’t accelerate. If I barely push the gas it will, but anything over 1/4 throttle and it just boggs down and won’t speed up. Im thinking some kind of sensor but idk. Any help is greatly appreciated! Update: Checked the trans fluid and it is still full. (1993 4 door 4x4 4.0l automatic)

 

[Blue m&m]

Could be a fuel issue. How’s the throttle response when you are in neutral?

 

[1993gen1eh]

Could be a fuel issue. How’s the throttle response when you are in neutral?

When it is in park or neutral it’s completely normal, only when I put it in gear it won’t accelerate past about 1/4 throttle.

 

[974X4BLACKSPORT]

Check you fuel pressure, most importantly when under load like accelerating. If you have not changed the fuel filter might try that see as it is a maintenance item. A clogged fuel filter will restrict the fuel and pressure and cause bogging under acceleration.,

 

[Blue m&m]

Agreed. I’d swap the filter and check pressure at the rail.....then if the issue persists, start diagnosing the transmission.

 

[974X4BLACKSPORT]

Also, a clogged catalytic converter will cause bogging/poor acceleration under load.

 

[1993gen1eh]

Also, a clogged catalytic converter will cause bogging/poor acceleration under load.

Ok thanks ill try both of those. Do you know how I can check the pressure?

 

[Dora 1993]

I had the exact same problem on a different car and it was the catalytic converter plugged. You can test them with a thermometer laser gun or by taking out o2 sensors.
You can borrow a fuel pressure gauge from an auto parts store. There's a Schrader valve on the fuel rail or lines under the hood you screw the hose onto and then crank and run the engine to see what pressure you have. I don't know what the right pressure is but I'm sure a little research will tell you.

 

[1993gen1eh]

I had the exact same problem on a different car and it was the catalytic converter plugged. You can test them with a thermometer laser gun or by taking out o2 sensors.
You can borrow a fuel pressure gauge from an auto parts store. There's a Schrader valve on the fuel rail or lines under the hood you screw the hose onto and then crank and run the engine to see what pressure you have. I don't know what the right pressure is but I'm sure a little research will tell you.

Ok thank you! I guess the next thing I’m gonna do is get a new exhaust system and replace the old catalytic converters, or just run straight exhaust with no cats. I replaced the fuel filter and cleaned the throttle body today and I think it fixed the problem. I’ve seen pond water 10x cleaner than what came out of the old fuel filter lol. So far since I bought it I’ve replaced: Spark plugs, plug wires, oil & filter, added trans fluid, fuel system cleaner, fuel filter, air filter, cleaned throttle body, and fixed the 4x4 which wasn’t working. Anything I forgot to do in the maintenance dept?

 

[Dora 1993]

Make sure everything is tight in the front end and tires wear even. make sure the coolant is in good condition. Clean the MAF. Clean the IAC. Inspect the brakes.
The list could go on for a novel or two with 25+ year old cars haha
I don't mess with anything until its broken otherwise my bank account would be broken