Rough idle, die when given gas


Teckus

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So I bought a 1990 2.9l ranger for 340$ with 160k motor in it. It ran fine for a week, now I go to start it itll run fine for 1-2 mins then all the sudden have a really rough idle and it wants to die when given gas.
 


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wildbill23c

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Throttle position sensor maybe? Not 100% certain, somebody with far more information than I have should know.

I'm currently dealing with an 87 Ranger with issues while trying to accelerate after its warmed up, and leading me to a similar issue and kind of leaning towards the TPS right now as the culprit...mine will sometimes idle weird and die too.
 

Nez'sRanger

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It's best to start with the basics. I've had several problems with my truck, and it would turn out to be something dumb, like I forgot to plug a sparkplug wire in. Check for any wires that are unplugged (or recently chewed by a squirrel).
Are there any engine codes? That's always helpful to know too. Of course, these old trucks can run on half a lung and still not spit out a code...
I would then go to testing fuel pressure and the fuel pressure regulator (fpr). Make sure it's not blowing gas in the vacuum line on the back of the fpr.
Changing sensors should be done only after testing them. It gets expensive if you do what I did and start changing stuff with the slightest indication that it may be at fault.
Check all that stuff and report back. As you give more info as to what is good and what you have already checked, we'll hopefully be able to pinpoint your problem with you!
 

Teckus

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It's best to start with the basics. I've had several problems with my truck, and it would turn out to be something dumb, like I forgot to plug a sparkplug wire in. Check for any wires that are unplugged (or recently chewed by a squirrel).
Are there any engine codes? That's always helpful to know too. Of course, these old trucks can run on half a lung and still not spit out a code...
I would then go to testing fuel pressure and the fuel pressure regulator (fpr). Make sure it's not blowing gas in the vacuum line on the back of the fpr.
Changing sensors should be done only after testing them. It gets expensive if you do what I did and start changing stuff with the slightest indication that it may be at fault.
Check all that stuff and report back. As you give more info as to what is good and what you have already checked, we'll hopefully be able to pinpoint your problem with you!
I was going to get a fuel pressure tester but no auto parts near me has one and I dont know much people around here so I stopped on trying that, there is no engine codes, or any lights on the dash for that matter. I checked all the wires and they seemed fine and snug in there. I did check inside the throttle body just by opening the butterfly valves and a flashlight and it looked VERY dirty so I lm going to clean that tommorow.
 

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So it runs fine for the first couple minutes means its running on preset parameters. Once it warms up the ecu wants to use the engine sensors including the o2 sensor. The cel may not come on but check for a code anyway. Could be the o2, could be the temp sensor (has 2 wires, not 1).
 

Teckus

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So it runs fine for the first couple minutes means its running on preset parameters. Once it warms up the ecu wants to use the engine sensors including the o2 sensor. The cel may not come on but check for a code anyway. Could be the o2, could be the temp sensor (has 2 wires, not 1).
I have 2 engine codes, 21 and 24, would this make it stall out?
 

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Yes, both can cause your issues

The main one is 21-Engine Coolant Temperature (ECT) sensor out of range
24-Intake Air Temperature (IAT) sensor out of range

2 digit code list here: https://therangerstation.com/tech_library/2digitcodes.shtml

ECT sensor is near thermostat housing along with the ECT SENDER(for temp gauge)

ECT sensor is 5volts and uses 2 wires
ECT Sender is 12volts and uses 1 wire

ECT sensor is only used by the computer, it is used to Choke the engine on start up and then adjust fuel mix according to engine temp
Check its wires first makes sure its plugged in and wires are OK, if so replace it, its not expensive
Then see how it runs

Code 24 can be caused by ECT sensor not working, even though its another sensor, it reads air temp inside the intake manifold so should go up with ECT sensors increase in temp, thats what computer compares it to
IAT sensor is on the upper intake, drivers side, also 2 wires, it looks similar to ECT sensor on the outside
 

Teckus

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So I found the issue.... I ran out of gas. My gas guage doesnt work and thought I could make it more miles
 

alwaysFlOoReD

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So I found the issue.... I ran out of gas. My gas guage doesnt work and thought I could make it more miles
Oops....
Many of have done the same, just won't admit it...lol.
 

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I used to get some grief when I asked if someone could be out of gas, so I just quit asking :)

Good work on figuring it out, and posting the FIX

I spent an hour on a friends car trying to get it to stay running, even asked him when he last put gas in it, yesterday
Well he had a leak in the fuel line, and a broken gas gauge
Didn't I feel the fool
 
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Teckus

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I used to get some much grief when I asked if someone could be out of gas I just quit asking :)

Good work on figuring it out, and posting the FIX

I spent an hour on a friends car trying to get it to stay running, even asked him when he last put gas in it, yesterday
Well he had a leak in the fuel line, and a broken gas gauge
Didn't I feel the fool
Haha, I just didnt think it was gas because I've never ran out and it just kept starting so I was just confused.
 


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