[Hopsnake]

Hey all, this is my first post so sorry if I get anything wrong. I've recently been working on my S10 and have had a problem with it where the check engine light is on, and when the engine revs, right after, it drops very low and almost dies, but then returns to normal idle. I've recently changed the spark plugs, spark plug wires, and throttle position sensor because I thought that could be the issue. I can't for the life of me figure this out and would appreciate any help at all. Thanks!

 

[Rebel n Dirt]

Sounds like a clogged cat to me. These older computers didn't have a limp home mode. They could barely handle the fuel and spark map functions.

 

[Hopsnake]

Sounds like a clogged cat to me. These older computers didn't have a limp home mode. They could barely handle the fuel and spark map functions.

Cat like catalytic converter right? I'll take a look at it. Thanks for the help!

 

[Rebel n Dirt]

Yup that's the one!

 

[Hopsnake]

Yup that's the one!

Awesome!

 

[Rhotpursuit]

Awesome!

If it has the original pancake convertor, it's past time for something up to date.

 

[Hopsnake]

If it has the original pancake convertor, it's past time for something up to date.

Sounds like a great plan, almost everything is stock on it so I'll check up on it. Anything else I should replace from your experience?

 

[Rebel n Dirt]

Sounds like a great plan, almost everything is stock on it so I'll check up on it. Anything else I should replace from your experience?

Just make sure the nut behind the steering wheel is good and tight!

 

[Hopsnake]

And this could throw a service engine soon light, right?

 

[Rhotpursuit]

And this could throw a service engine soon light, right?

Yes...alternating red/blue.

 

[Hopsnake]

Yes...alternating red/blue.

I'll make sure to keep an eye out for that lol.

 

[Rhotpursuit]

 

[Hopsnake]

The only bad part about it is I can't pass emissions now, which sucks.

 

[Rebel n Dirt]

Obd 1 (or ALDL in GM speak) has no cat health monitoring capabilities.

 

[Hopsnake]

Obd 1 (or ALDL in GM speak) has no cat health monitoring capabilities.

And so the search starts again!

 

[Jayhawke]

cap,rotor, fuel filter, then get a aftermarket cat to fit.

 

[Hopsnake]

cap,rotor, fuel filter, then get a aftermarket cat to fit.

I'll make sure to do those

 

[dtjdcttoc]

Hey all, this is my first post so sorry if I get anything wrong. I've recently been working on my S10 and have had a problem with it where the check engine light is on, and when the engine revs, right after, it drops very low and almost dies, but then returns to normal idle. I've recently changed the spark plugs, spark plug wires, and throttle position sensor because I thought that could be the issue. I can't for the life of me figure this out and would appreciate any help at all. Thanks!

Hello, did you check to see which code it's throwing since the check engine light is on?

 

[Hopsnake]

Hello, did you check to see which code it's throwing since the check engine light is on?

I did! It's just throwing 21 over and over again, the website I checked said that it's a TPS but when I replaced it the car didn't stop the code.

 

[dtjdcttoc]

GM OBD Trouble Code 21
Throttle Position Sensor Error (Signal High)
The Throttle Position sensor signals the Engine Control Module as to the current position of the engine throttle valve. The current throttle valve opening is based on the driver's input from the gas pedal. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.
Fault Code Description

• 21 - Throttle Position sensor error (signal high, open circuit)

Symptoms

• Extended cranking, possible no-start condition
• Lack of power
• Erratic transmission operation

Common Problems

• A failed Throttle Position Sensor (TPS) or broken wires near the sensor are the most common causes for code 21
• Testing the TPS circuit would involve checking voltage and ground from the ECM—5v is the normal reading between the ECM reference circuit and the ECM ground circuit at the TPS connector. Checking the TPS signal circuit to the ECM would involve monitoring the TPS signal on a scan tool while jumping the 5v reference and the signal circuits. The TPS reading should go from high when the circuit is "jumpered" to low when the jumper is removed.

Broken wire near the sensor a good possibility.