Robotman2011

Ok...I have struggled with this issue for about a year now. I even saw a post that was similar and tried some of the recommendations...I can't find the post now though... Here goes

Everytime I get to 2300 to 2400 rpms my motor stutters... It is almost like the motor bogs down but I don't know if that describes the issue most accurately. I have done the following... Btw my 1998 camaro has 81000 miles on it... Tune up new plugs wires etc... Fuel injector servicing....o2 sensors have all been changed... I have sea foamed the gas and motor and the throttle body has been cleaned.

I took it to he mechanic and he did the tune up. along with fuel injector servicing on it. When it was still stuttering, he put together a plan that said thAt he cats were going bad... Gave me a quote of 1100 to fix those....didn't have that kind of money lying around ... Also wasnt too sure about that given that the stuttering or bogging down stops once I get to 2500 rpms. So i took it home. It seemed to run a little better. In fact the motor would run normally...still stuttered though...when I would push down on the gas to pass then I would get a service engine soon light...took it to A muffler shop and they said the cats were good but the o2 sensors were throwing the code...so changed all 4 o2 sensors...still stuttering...so I sea foamed the motor and the gas.... It seemed to do better but still stuttering. So I am at a loss about what to do next. I am noticing that my pressure gauge needle is wiggling back and forth slightly .... From what I can tell from he forums on here it seems that is my oil sendin unit / sensor. Could that be causing my stuttering? Also could it be the fuel pump? Any advice would be greatly appreciated. I am really starting to learn more about my camaro since it it starting to get some miles.

RPM WS6

iTrader: (3)

First off, forget about the cats, they are not your problem. If they were clogged enough to cause driveability issues at 23-2400rpm, then the engine certainly wouldn't run better at even higher rpms. I have no idea what would make any mechanic suggest that as a possibility given your symptoms (issues only at 2300-2400, no problems at higher rpms), but it makes the rest of his judgement and work suspect IMO. In other words, I wonder if you still might have a spark plug or wire issue, causing an intermittent misfire. Maybe the "tune up" he did wasn't so good.

Secondly, a bad oil pressure sender would not cause any driveability issues at all, so that is certainly not your problem here.

In all the cleaning of various items that you have done, have you ever cleaned the MAF? I would suggest to do that next. They make cleaner sprays that are designed for the MAF, but I prefer the old method of Q-tips, rubbing alcohol and a gentle touch.

Also, is the car a manual? Do you hear any abnormal ticking from the valvetrain? Ever missed a shift at WOT and hit the rev limiter really hard, or accidently forced a mechanical overrev (like an accidental downshift to 1st when trying to upshift to 3rd)?

Robotman2011

Hey thanks for posting man

I was thinking the same thing about the cats. What is the MAF? Are you thinking the mass airflow sensor?

Also...it is a manual shift transmission. I haven experienced an issue like you describe as far as the redlining the motor. I was hinking this could be a failing fuel pump but that doesn totally sound right either... Oh yeah when this first started i changed the fuel filter. One of the good hings about changing the o 2 sensors has been no service engine soon light . Moreover everytime i have done something the car seems to have started running better...just can kick this stuttering.

Also i dont here any ticking from the valve train.. I do here something akin to a rattlesnake sound when i take off... That could be thouht of as a clicking sound but it is not coming from the top of the motor... Im thinking throw out bearing or something with that sound since it seems to be comin from the transmission/back engine area.

jimmyblue

iTrader: (11)

I'm wondering if it's something like you straddling the FTC
(fuel trim cell) boundary - which is really 2500 in stock
F-body tunes - and the trim is really whacked, such that
step over the line and your mixture gets bent so you fall
back under, rev back, on and on.

If you are scanning, see if the "stumble" is showing you
bumping back and forth between trim cells and seeing the
trim values rattling around.

Of course there also are a number of RPM-indexed tables
where a kooky cell value could make things nonmonotonic
and thus bistable / notchy as you slide across it. Looking
at them individually for eyeball-wrong curves / surfaces
is worth some time spent, if you can.

myk

iTrader: (4)

The shaking oil pressure gauge is normal for a lot of our cars, it's not the issue. Try cleaning the MAF, and don't be so sure about your fuel pump/pressure until you've measured it. Although, in my experience a bad fuel pump quits or messus up on much higher RPMs, not on the lower side of things. Couldn't hurt to check and make sure all plugs and wires are good, too. No telling what this mechanic did or didn't do properly...

WS6 Rampage

iTrader: (3)

Im with everyone else, hose down the MAF w/ cleaner and recheck the plugs. If anything, go down to AutoZone and let them plug into your OBDII and pull the DTC codes. It's free.

RPM WS6

iTrader: (3)

Yes. Like a couple of us have mentioned now, clean the MAF and recheck the plugs and wires, that's where I would start.

Jimmyblue also offered some great ideas for scanning which may point you in a specific repair direction, but you won't be able to do that without a comprehensive scanner, which you may or may not have.

RsSean

iTrader: (27)

Easy way to figure out what it's doing u need a misfire graphic so u can figure out what cylinder h need to go after. Lately I have had a lot of customers with coil issues. You can unplug the maf the car will go to sPeed desinty and would eliminate a maf issues

Robotman2011

Thanks everyone...I will try cleaning the maf....I will keep everyone posted.

Jimmy blue thanks for your post...I'm not sure I understand everything you are saying though...how do I go about checking what yo are talking about?

omarrakeen

iTrader: (2)

make sure it isnt a valve train issue before dumping money into it. have it scanned and start with the first code you get. it could be anything! and i also agree with rpm ws6 on the mechanic, id double check his work on the tune up just for the piece of mind. good luck.

Robotman2011

I checked the plug and plug wires with my dad...they look new. Also after I had that done, the car seemed to run better and more smoothly. Btw, I also was thinking...why not buy a new mass airflow sensor? Then I saw the price. I see why everyone is recommending to clean it. Thanks again for the advice.

omarrakeen

iTrader: (2)

you can borrow one from a friend. try it out and see how it goes..

myk

iTrader: (4)

You'd need a scan tool, or a code reader that can read "live" data streams from the computer as the car runs. I've been thinking about buying one myself-they go for a few hundred bucks but I think they're well worth it...

99VetteFRC

I have a Snap on Scanner updated to '06 with asian for $200.00. I have close to $4k invested over the last 10 years but its out dated for using in the dealership on new cars. If anyone is interested just email me. parasitess@hotmail.com

Robotman2011

I just wanted to say thanks to everyone for their help. I cleaned the MAF and haven't had a stutter since i did that. There was this caked on dirt on the metal things going across the intake tube. Good call everyone!

RPM WS6

iTrader: (3)

I've found MAF cleanings to clear up driveability issues on several cars over the years, even including certain transmission performance issues (auto).

Glad that fixed it. Nothing like the feeling of finally defeating an issue that's been bugging you so long.

Robotman2011

Yeah it feels great especially when i am getting on the freeway.