TobyZ28

I'm really getting pissed off at this low RPM stumble thing... and can't figure out why it's happening... I'd like to ask ONLY those who have solved the following exact symptoms, no higher rpm stumble or anything else, but exactly the following:

-Stumbles ONLY when engine is warmed up.
-A cold engine always feels strong.
-No service engine soon lights come on or are on.
-Stumble is only apparent accellerating starting at roughly 2k rpm.. it feels like it bogs down. If you push harder it'll jump up to around 3k rpm and continue fine after that.
-The car idles fine.
-It won't stumble when out of gear, or if your WOT from a stop.

I've just noticed a lot of posts about trying to solve it but it can be one of many problems and often peoples symptoms vary alot and are likely many different things...
I'm so frustrated with all this because I just spent big cash rebuilding my damn engine and the stumble is still there, the electronic sensors, injectors and opti are all from the last engine.

Please only reply if you've had those exact symptoms and have solved it! thanks!

94GrayV6

I've got the same crap going on, so TTT for you.

I've replaced everything except for the O2's and the ignition control module.

funina91ss

I would try to space mod in the ICM if it only does it when its warm something must be getting hot. a couple of w and your done..

got_hp?

replace the O2s!!!!!

94GrayV6

I already did the mod. Thanks for the help though!

TobyZ28

I can't afford to replace this and that on my car, I need to make the best decision when replacing parts. I've replaced my O2's less than 4 months ago.
What i'm hoping for then is someone whos had the exact same symptoms and let us know what that is... if its the ICM or the O2's fine, but i really want to hear it from someone whos had the identical symptoms solved. I'll try the washer thing tho, that should be pennies and good for the car anyhow

Cmr0z28

did you make sure your EGR valve isnt sticking? i have a similar problem from like 1000-1200 at VERY LIGHT throttle in first gear....the car feels like its trying to pull 5 tons and is being held back, then when it gets to 2nd gear it shoots forward....my EGR valve feels like its sticking so im just gonna rip it off when i get headers and a pcmforless.com program

94GrayV6

My problem is at a higher RPM. 2k or so which usually means 40-50 mph. Whenever I tip into it, sometimes it sputters.

NVetro

Guys witht his issue. I have had the "sputter" at low rpm and in low gears and in high gears at all speeds. I replaced the coil, plugs, wires, opti, fuel filter, etc.. etc... I recently fixed this issue, atleast i feel its almost kinda fixed. I took off my MAF one day and found BLACK carbon literaly caked on the screen and the sensor inside of the MAF (3 wires). I suggest you get some enigne degreser and spray the hell out of it, and pluck holes in the screen where the spray wont get to. This helped SO much. Try this, all of you. I still feel the sputter, its ALOT better. But its still there, alittle. Next thing i am doing is O2's, and then Fuel Pump, then I will truly be stumped.

94GrayV6

Yeah I just cleaned the MAF the other day too. There was so much crap on it that when it was sprayed, all the gunk ran off and made a ring on the ground that could be scraped up with a screwdriver.

Vader

Did you use GM O2 sensors? If not the aftermarket ones may be the problem. I used Bluestreak O2's and they seemed to work for a few months, and then one became intermittent and caused the kind of bog you describe. If one bank has darker sparkplugs than the other, that's the problem. As long as the O2 functions partially it may not pop a code. Mine didn't until the very end.

got_hp?

get AC Delco O2's, not Bosch or anything else.

94formulabz

coil.

CCRJon

With the kinda harsh temp changes in the Northeast part of the country, My spark plug wires and boots were cracked and brittle. I replaced them, along with adding new sparkplugs (Splitfire Platinums) - then the beast came back to life. The stumble was gone and now I only have to worry about what mod to do next.

I think suspension work....................

Fatdog

I fixed mine unknowingly.About a week before my car died,it had the off idle stumble,then one morning it would crank but no start.So I threw the towel in,had it towed to the dealer(thinking it's opti time)and to my suprise,,it was most of my old decaying wireing and Connectors going the the map sensor and to the iac,along with those little hoses(vaccum).All this stuff is on top of the engine(pass side).Had the throttle body cleaned as well,now the car screams all the way up to the limiter.Hope this helps.(no more off idle stumble for now thank GOD.)