RPM flutter

[TYZAPOLI]

New owner. I've put about 6000 miles on it since i've purchased it totaling milage to 66,000. I didnt a tune-up on it with all the reccomended products i've read about on these forums and the things seems to run great. The only concern I have is that there is an RPM flutter. When sitting at idle it seems to jump around a little bit, maybe 50prms. It is more noticable when in gear and stopped at a light. Just wondering if this is something that is charactoristic of these engines. Any help would be appreciated.

 

[BMFB]

Re: RPM flutter

Its voodoo man, 66 thousand miles is unlucky for these trucks, and you say you put 6k on yourself, thats just horrid luck. I would say your best bet would be garlic, hang some under the hood, get some of that powdered garlic, and put it in your gas tank, not that cheap stuff, get McCormick.

Also, a 50 rpm flutter isnt bad, but with the milage and age id say it could jsut be some gunk in your IAC valve, they're kinda known for this. its a module in your throttle body, on the backside where its hard to see. i believe its got a pretty good sized 4 prong connector, and its held in with torx screws. its harder to clean right on these trucks than it was on my caprice, cause to spray anything into the throttle body iteslf, you have to remove your intercooler, or take the whole throttle body off. But id would look into the module, remove it, and see how nasty it looks, clean it, spray some carb cleaner into the IAC 'chamber' and maybe try to clean it with a rag or something.

Also, dont put garlic in your gas tank, that will only make it worse, it was a dumb joke, brought on by nightquil. you can hang garlic, as much as you'd like, hell, that might even be cool.

 

[TYZAPOLI]

Re: RPM flutter

I'll give it a shot. I remember jumpering the iac out to ensure it was actually working but havent gotten into ripping it off to clean it up. Didnt notice all those 6's when i wrote that but it was a fat finger mistake anyhow so hopefully i have better luck since its actually 56k.
I might need to put some garlic on the inside though because moth balls stink and like to linger even when they've been removed.

 

[CC801]

Re: RPM flutter

50 rpm is normal. you can take any 2011 car put it on the scan tool and the idle will vary at least 50 rpm. they may set a certian car @700 rpm but it is constantly trying to stay at 700 rpm it may range from 675-725 or more. the pcm is correcting itself thousabnds of times per min. you may not see it on the tach, but put it on a scan tool and you'll see it.

 

[dgoodhue]

Re: RPM flutter

It's common for the idle to be a little jumpy and have a slight misfire every once in a while with the stock chip. When I first bought my truck, I tried many things to get rid of it (back when it had 42k), nothing helped [tune up, IAC, new gaskets, rebuilt distributor, top end cleaner, new O2 sensor.]

 

[TYZAPOLI]

Re: RPM flutter

Yeah, i can see it on my tach and like i said before its actually more noticable when in gear and parked. I plan to get the scan tool and get a good tune out of it when I get some more cash. But I'm not racing it yet. Just having fun driving it around town. I got it from the original owners son who knew nothing about the thing. She passed away and it was in storage for 8 years. She used it as her luxury sunday cruiser. The outside condition is great but the suspension bushings are tired and weathered. I appreciate your guys' help. This forum has been helpful just by browsing around.

 

[BMFB]

Re: RPM flutter

I was thinking his interpritation of 50 rpm was a guess, if its a noticible....surging, than its something that can be fixed ususally. if its been tuned buy someone with say, CODE59 then its a tune issue, but yes, a goofy idle, random inexplicable misfire, leaks, all normal with these trucks.

 

[TYZAPOLI]

Re: RPM flutter

Its never been tuned by anybody. Has had no record of codes and the drivability is flawfless as far as engine performance. No hesitations, no oil leaks. Just a little bit of blue smoke on start up but I've read thats normal and remember having the same issue on my 94 S-10 Blazer about 10 years ago.

 

[BMFB]

Re: RPM flutter

yea, thats valve guides and seals. buts likly that IAC module, at leasts thats where I would look first. Then on to your vacuum line network for leaks!

 

[dgoodhue]

Re: RPM flutter

yea, thats valve guides and seals. buts likly that IAC module, at leasts thats where I would look first. Then on to your vacuum line network for leaks!

Its Valve seals causing the puff of smoke. Valve guides are pressed into the head and those don't normal wear out unless you have super high miles.

 

[SY2932]

Re: RPM flutter

When I switched to NGK UR5 (part number 2771) spark plugs as did many others when they were "new" many years ago, it helped my truck idle better than the AC Delco's did.

 

[bonesdmz]

Re: RPM flutter

Its voodoo man, 66 thousand miles is unlucky for these trucks, and you say you put 6k on yourself, thats just horrid luck. I would say your best bet would be garlic, hang some under the hood, get some of that powdered garlic, and put it in your gas tank, not that cheap stuff, get McCormick.

Also, a 50 rpm flutter isnt bad, but with the milage and age id say it could jsut be some gunk in your IAC valve, they're kinda known for this. its a module in your throttle body, on the backside where its hard to see. i believe its got a pretty good sized 4 prong connector, and its held in with torx screws. its harder to clean right on these trucks than it was on my caprice, cause to spray anything into the throttle body iteslf, you have to remove your intercooler, or take the whole throttle body off. But id would look into the module, remove it, and see how nasty it looks, clean it, spray some carb cleaner into the IAC 'chamber' and maybe try to clean it with a rag or something.

Also, dont put garlic in your gas tank, that will only make it worse, it was a dumb joke, brought on by nightquil. you can hang garlic, as much as you'd like, hell, that might even be cool.

:rotf:

 

[BMFB]

Re: RPM flutter

I was wondering if anyone else would think that funny, I was pretty messed up this morning thanks to a recommended dosage of nightquil...