My 2000 blazer is doing a couple of different things. When im driving on the highway the rpm's goes back and fourth from 1800 to 1400 and acts like its cutting out. sometimes it does that when I stop and it stalls. I replaced the tps, maf, distributer, cap,rotor, wires, plugs, temp sensor. Fuel pressure is good. Codes say tps circut low. Garage told me it was a bad ground. They fixed it and it was good for 100 miles then back to doing it. Is there a common ground problem and which one?

It is still doing what it originally did. So its not fixed yet. Just replaced the tps sensor again and still is doing the same thing It is still doing what it originally did. So its not fixed yet. Just replaced the tps sensor again and still is doing the same thing

Bad ground you are a three wire sensor, dark blue,black,grey, The Grey is 5 volts reference, Black is ground,Dark blue TPS sensor signal, If the TPS has low input, the coolant tempsensor share the ground,and the coolant temp sensor should be affected,How did you get the code? If you have a code reader then we will have to verify the signal, First remeber if you change the TPS you have to clear the code or it will stay in limp mode till you clear it, . Now lets trouble shoot the TPS sensor connector needs to be inspected for bad male and female connection . with that in good shape we will need to verify the ECM, with code clear key on disconnect the TPS, start the engine and allow the vehicle to give the code TPS high circuit, If the code comes on we then will know that the signal wire can sense the circuit input, clear code ,put sensor back on start the vehicle,allow the circuit to run it process, The best way to resolve this is to trouble shoot the wire ourself if you have a digital volt meter it has to be used, here goes we need to measure the wire key on engine off, lets check reference voltage (try not to seperate the terminals) disconnect TPS what is the voltage you hhave at the grey wire, it must be five volts, now measure the black wire, what you are going to measure is known as a voltage drop this is what the garage said they fixed this voltage cannot exceed .05 volts if it does this will need to be repaired the voltage is allowed to be .02 and below, I need engine size and do you know if you are drive by wire or cable I need the engine size Bad ground you are a three wire sensor, dark blue,black,grey, The Grey is 5 volts reference, Black is ground,Dark blue TPS sensor signal, If the TPS has low input, the coolant tempsensor share the ground,and the coolant temp sensor should be affected,How did you get the code? If you have a code reader then we will have to verify the signal, First remeber if you change the TPS you have to clear the code or it will stay in limp mode till you clear it, . Now lets trouble shoot the TPS sensor connector needs to be inspected for bad male and female connection . with that in good shape we will need to verify the ECM, with code clear key on disconnect the TPS, start the engine and allow the vehicle to give the code TPS high circuit, If the code comes on we then will know that the signal wire can sense the circuit input, clear code ,put sensor back on start the vehicle,allow the circuit to run it process, The best way to resolve this is to trouble shoot the wire ourself if you have a digital volt meter it has to be used, here goes we need to measure the wire key on engine off, lets check reference voltage (try not to seperate the terminals) disconnect TPS what is the voltage you hhave at the grey wire, it must be five volts, now measure the black wire, what you are going to measure is known as a voltage drop this is what the garage said they fixed this voltage cannot exceed .05 volts if it does this will need to be repaired the voltage is allowed to be .02 and below, I need engine size and do you know if you are drive by wire or cable I need the engine size