Hey folks,

The new 5.8L runs like a scolded dog...Although, I am getting a rather higher then normal idle-surge issue. No codes....

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Once the truck is warmed up after I drive it around to work ect... I put the trans in the park position the RPMs will stay around 1200 RPM until I tap the gas.... Then it drops back down to normal range around 800-900.

Then about 10 seconds later it will start to have a slight engine surge issue from 800-1000 RPM.

Then back to about 1200 RPM idle issue. ect... repeat.

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Timing is set at 13 degrees with the spout out.

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I pulled the IAC connector when running and it drops down to about 600 RPM and idles perfect...I plug it back up and engine dies...I crank it back up and the surging....Higher then normal RPMS repeat ect...

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Why I think it might be the oxygen sensor placement.... I have it currently in the Driver side Long Tube header....Currently running true duel exhaust....

The bung for the passenger side header is about 1/4" to high and the sensor hits the Trans casing lip....I could grind a small piece off the lip....

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Any ideas?

Sorry about the terrible pictures....Cant crawl under truck with out jacking it up.

 

Sounds like a vacuum leak and since your actuating the throttle body, the blades may be worn or your linkage is sticking.

 

The O2 sensor location is not your problem. You may have a worn throttlebody, a sticking IAC valve, or a bad TPS sensor.

 

I?dle surge typically isn't o2 sensor. You could unplug the sensor and see if that's your issue, but I've never seen an o2 sensor not function when it's in the header...that's plenty close enough.

What headers are theY

 

Thanks.

I still have the throttle body and all its goodies from 5.0L that I will swap over and give it a try.

Vacuum leak. I tried spraying all around upper plenum gasket and throttle body area and did not notice any thing. Hard to tell with the issue.....Think ill unplug the IAC and spray again....

I got a ghost in the machine it seems....got home for work last night and put it in park and the issue was gone..... Seems like the warmer-cooler temperatures outside have something to do with it. ACT sensor acting up?

 

BAD DOG!... BAD-BAD-DOG!!



Sorry, couldn't help it.

 

Swapped the IAC valve from my 5.0L engine onto the 5.8L engine...Problem solved.

It looked like it was stuck...