“CAI” cause of RPM fluctuation?

[AC95]

I have the CAI (just a tube with MAF hole) off of a junkyard Tahoe.

Last Friday or Saturday I left in the morning around 7 and then stopped to get an iced caffeine beverage; The engine engine started up without issue… getting on the road the second time, I came to a stop at a red light, accelerated off when it turned green…. Then the DIC began flashing “be careful ice possible” or something like that… then the engine went into limp mode…. And said “power reduced”. I think they happened at the same instance.

The engine just like stopped accelerating and I was Alright let’s go what’s Good.

Did the CEL come on after that? I don’t know, it was aready on from after filling it up all the way for the first time. Gas cap?????

And now…. About 5 times over the past week, when I’ve come to a stop at a red light…. As the rpm’s fall to idle, (600) instead of right away finding itsself at 600, the dial jumps jumps and feels like it’s gonna shut off…… when I put it in neutral, they find themself.

Is this a MAF related thing with there being more air..

Is this a transmission issue, a sensor?

Is this a bad torque converter?

Maybe new spark plugs would be good…. Maaaaan SPARKPLUGS.

The vehicle ran good before the CAI; exhaust manifold gaskets are leaking. So besides that, the engine ran good.


… Thank you

 

[RichardCranium]

Could be many things going on here. My first thoughts are a vacuum leak, since you swapped out the induction. Any pics of the setup? Was the CAI some sort of universal kit, or does it appear to fit like its made for a GMT900?

Much easier to use the K.I.S.S. method (keep it simple, stupid) here since it ran fine before the CAI swap. I'd double check to make sure a clamp/rubber fitting didn't slip off around the throttle body. Assume there are no open holes in the elbow, for anything like an IAT?

 

[Fless]

IIRC the IAT is combined with the MAF. If it wasn't particularly cold when the 'ice' warning came on, that's an indicator that the IAT isn't reporting correctly. Might just be a dirty or bad MAF.

Can you reinstall the OE air intake to see if that changes anything?

 

[RooTBeeRthe1st]

Definitely some sort of MAF error. Certainly not helping your issue with leaking exhaust gaskets, I'm sure that's making it run slightly Rich to begin with. But like the others mentioned, check to make sure that your MAF connector and wires are plugged in and tight. Also check to make sure the MAF sensor is sealed on the intake tube, and then make sure that the intake tube doesn't have any leaks going between the MAF and the throttle body.
But also yes, installing some cai"s can cause it to run a little lean without getting it tuned even if they say there's no tune required.
When I put on my Corsa supposedly you don't have to do anything, but it didn't take long before it maxed out the fuel trims because it was reading so far off from the stock intake.

 

[AC95]

Could be many things going on here. My first thoughts are a vacuum leak, since you swapped out the induction. Any pics of the setup? Was the CAI some sort of universal kit, or does it appear to fit like its made for a GMT900?

Much easier to use the K.I.S.S. method (keep it simple, stupid) here since it ran fine before the CAI swap. I'd double check to make sure a clamp/rubber fitting didn't slip off around the throttle body. Assume there are no open holes in the elbow, for anything like an IAT?

This may just be a universal kit, unsure

 

[AC95]

Definitely some sort of MAF error. Certainly not helping your issue with leaking exhaust gaskets, I'm sure that's making it run slightly Rich to begin with. But like the others mentioned, check to make sure that your MAF connector and wires are plugged in and tight. Also check to make sure the MAF sensor is sealed on the intake tube, and then make sure that the intake tube doesn't have any leaks going between the MAF and the throttle body.
But also yes, installing some cai"s can cause it to run a little lean without getting it tuned even if they say there's no tune required.
When I put on my Corsa supposedly you don't have to do anything, but it didn't take long before it maxed out the fuel trims because it was reading so far off from the stock intake.

Thank you for the help!! Yes! Rich from exhaust!

 

[AC95]

I did the test of removing MAF when the crazy idle wa happening… and the engine smoothed out. Plugged it back in and the crazy idle came back.

I swapped out the MAF that was present in my vehicle with the sensor that came with the CAI tube… and the crazy idle and “low power” limp mode stuff went away. I think the higher flow fried the MAF sensor? Or as I mention below, the battery can’t do it’s delivery enough power.

I also put in new spark plugs, went with the ruthenium plugs. The others were probably stock… 77k miles stock… or maybe changed at like 30k or something. Either way; they were beat…. And the engine really responded with more sensitivity and intensity upon pressing the gas pedal…..

My battery is also way to small for this elephant, so I’m going to get the correct one today…

 

[Geotrash]

I did the test of removing MAF when the crazy idle wa happening… and the engine smoothed out. Plugged it back in and the crazy idle came back.

I swapped out the MAF that was present in my vehicle with the sensor that came with the CAI tube… and the crazy idle and “low power” limp mode stuff went away. I think the higher flow fried the MAF sensor? Or as I mention below, the battery can’t do it’s delivery enough power.

I also put in new spark plugs, went with the ruthenium plugs. The others were probably stock… 77k miles stock… or maybe changed at like 30k or something. Either way; they were beat…. And the engine really responded with more sensitivity and intensity upon pressing the gas pedal…..

My battery is also way to small for this elephant, so I’m going to get the correct one today…

Glad your initial issue seems to be resolved. Also, that plug looks fine to me.

 

[RooTBeeRthe1st]

Glad your initial issue seems to be resolved. Also, that plug looks fine to me.

Yeah, doesn't look good/new, but not bad at all.

 

[CrashTestDummy]

Agreed. That plug looks used, but not abused. I replaced the plugs on our '10 Tahoe when we got it at ~60K miles, just because. While they didn't look as used as the one you show, the new plugs made zero difference in how the truck ran.