91 S10 blazer High idle in park

AAiRR said:

I’ve replaced the IAC, the whole throttlebody the MAP and I have sorta checked for vacuum leaks. But it idles high in park 80% of the time. But in all fairness I don’t have any exhaust after my cat . So I’m missing an O2 I’m about to replace that with this coming paycheck . But I’m wondering if anyone has any ideas tho

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It would only have O2 before cat(s). CEL should be on if you don't have any. In that case it wouldn't run properly if at all. Mo info on combo mite be helpful.

Don’t “sorta” check for vacuum leaks; fully check for vacuum leaks. I don’t know that OBD1 allows you to check O2 sensor signal, but using a multimeter to monitor O2 sensor voltage while searching all vacuum lines and gaskets with unlit propane would probably serve the same purpose. You’re watching to see voltage spike. An oil leak is a vacuum leak. This is assuming that the O2 sensor is still installed before the cat. If it isn’t, the computer is looking for one.

Is the CEL on? Does it even work (illuminate key on engine off)?


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PeteD said:

It would only have O2 before cat(s). CEL should be on if you don't have any. In that case it wouldn't run properly if at all. Mo info on combo mite be helpful.

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I bought it with the exhaust missing from the Cat back. I just assumed it would have one after the cat I need to check into it. When I plugs a reader on it. It blinked 1-2 but I don’t believe it lol. I’m going to go thru it today and really really check for vacuum leaks everywhere I can think of. But I’ll be reading any suggestions you guys post as well and checking them too

AAiRR said:

I’ve replaced the IAC, the whole throttlebody the MAP and I have sorta checked for vacuum leaks. But it idles high in park 80% of the time. But in all fairness I don’t have any exhaust after my cat . So I’m missing an O2 I’m about to replace that with this coming paycheck . But I’m wondering if anyone has any ideas tho

Click to expand...

Check engine light on? Best thing with gen 1 just need a paperclip to check your OBC

I’ve went over the line and gaskets , repair the leaks and repaired a wire to the iac and boom she is idling perfect now

AAiRR said:

I’ve went over the line and gaskets , repair the leaks and repaired a wire to the iac and boom she is idling perfect now

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Always good to know when fellow enthusiast has diagnosed and then fixed their vehicle. There's never an end to learning problem solving.