1994 Ford Ranger acceleration issues

[wallywonks]

Hi everyone,

I have a 1994 Ford Ranger XLT 4.0L truck. 2 weeks ago the truck ran out of gas on my way home (fuel gauge hasn't worked for 3 yrs). I went to gas station and got 1 gallon of gas. Battery was dead when I walked back. I had to push it down the road and jump start it since it is a manual. Drove it home. Then next morning I filled it up at same gas station.

Okay, that was the situation before this started happening.

I have no Check Engine Light. When I try to accelerate from 2nd gear and up the truck seems to stumble and the truck shudders. I can get it up to speed but I can't punch it and get the immediate horsepower I should get. Also the exhaust is making a different sound than it used to. It not really a backfire but it is louder like ba ba ba ba ba ba ba. When it idles you hear like a bassy pop sound every few seconds.

Going uphill I can floor the gas pedal and it just chugged up the hill at only 35mph. Would not give me any power or speed. If I give it too much it will actually rev as if the clutch slipped into neutral until the rpm come down a bit and kick back in.

I had issues with the MAF sensor in the past 3 yrs. I usually have to spray it every 6-12 months. I sprayed it this time and condition still exists. I also tested the sensor to ECC wire while pulling on the throttle cable and baseline was 1.0v and it went up to 2.5v at almost full throttle. It doesn't jump erratically. It goes up and down nice and smooth. There is like a brownish red color on the one side of the wire on the MAF sensor when you look at it and not silver. Still there after spraying.

I tested the TPS with multimeter and was getting baseline .90 and it goes up to 4.5v when pulling on the throttle cable.

I replaced the ECC last February. The OEM one had 3 leaking capacitors and left me with a no start condition. The fuel pump constantly running tipped me off as this means the ECC wasn't grounding out so the fuel pump kept running. This problem has gone away since replacing it. The truck ran beautiful until this incident.

I used an OBD I code reader. KOEO test gives me 111 then 10 then 111. So it seems that test passed.

I then did the KOER test. It displayed the 6 cylinders. Then the 10 code which I floored the gas pedal. I get 2 codes.

1st code is 116 - Engine coolant temperature higher or lower than expected.

2nd code is 172 - HEGO (HO2S) sensor fault/lean

I have not checked the fuel pressure at the fitting on the rail yet. I am also aware that the fuel filter may be partially clogged.

I can get the truck to go up to 55 mph and be in 4th gear if the road is flat or downhill. But as soon as the speed comes down towards the low part of that gear it will shudder until I downshift. The clutch will stall the engine about half way letting clutch pedal out when not moving. The clutch disengages from the engine properly when pushed in.

I have not noticed any missing or broken vacuum lines and I have not sprayed around the intake manifold for leaks.

I assume you guys will suggest testing fuel pressure first since it ran out of gas and I have no idea how old the fuel filter is.

Let me know if you guys think it something that can cost $100 or if my transmission is going bad.

Thanks
Chris J

 

[cbxer55]

Same thing happened to me in December. It was a bad fuel pump. Had very low fuel pressure after the pump got warmed up. It was fine when first started, or after sitting for a spell. But 5 minutes or so later, no power. I could get it up to speed, but it would not accept any heavy throttle at all. Changed the pump, problem fixed.

Do you have a fuel pressure gauge? If not, get one. Auto Zone has one for a reasonable price.

 

[cbxer55]

I hooked up a gauge and let it idle in the garage. It was fine when first started, but about 5 minutes after the pressure started falling off rapidly. I guess when the pump gets hot, it starts to fail. After cooling off for a bit, it would be fine again. Then a few minutes later start falling.

I'm thinking that since you let the tank get empty, it may have damaged the pump. You should never let that happen. I keep mine above the half way point most all of the time. My Lightning as well, since it has two pumps that can go bad, EXPENSIVE!