Truck surging question?

(2012-02-01 15:20:26)

1. Mike Says: 95 chevy blazer,v-6. muffler blew out and patched it with sheet metal till payday, also think converter needs replaced too. the question is my kid has been driving it and its been surging, will the exhaust problem cause that, will it hurt the motor to keep driving it this way? im familiar with back pressure but not sure. fuel filter has been replaced and purged. thanks

2. kevusaborn Says: The muffler is not causing this surging, the oxygen sensor behind the catalytic converter or
behind the catalytic converter could be giving false reading to the computer which could cause
this type of problem. Do you have any lights on at the dashboard. ie MIL light Malfunction
Indicator Light ? If you have a light on, yes, this could hurt the motor .

3. Christian Says: a plugged/damaged exhaust system will cause a poor runability problem. you mentioned back pressure so you now you need it

another problem, could be bad gas, dirty iac, dirty injectors or with this vehicle the fuel injection spider can cause problems

4. bandit_60 Says: you mean the idle comes and goes ? start it up and hold the gas down a little bit. if the surging stops then you have a vacuum leak. it also could be the fuel pump too.