FAQ: Hesitation, Stutter(Studder), Shudder, Stumbling, on Acceleration/Load

charlieRobinson wrote:

Wait.... so putting your car in P or N and revving is bad? ....

Short answer---yeah its bad, don't do it. Ever.

Longer answer -- the rive is cammed for low end torquer and not for high revs. If u want a high rev engine get an engine made to rev high, NOT a 3800.

"If u want a high rev engine get build an engine made to rev high, NOT even a 3800."

joshuadalegrimes wrote:

mass air code is only one and its getting fixed with new sensor and as soon as i find them wires.

plugs are new, wires are not

seafoamed it about 3 months ago

165xxx miles ive put 35xxx since i bougt it a lil over a year ago. all reg maintence done plus new front hubs, new fuel pump, repaired fuel lines, radiator has been flushed when i put in 180 thermo, thats all i can think of and when i get back to atlanta next month ill do a video of what its doin

Wait, you have a MAF code but you are going WOT? stop stop stop! Be very very gentle with that throttle if your MAF isn't working properly.

If your check engine light is on, forget about WOT. Just go easy until that problem is fixed.

AA wrote:

"If u want a high rev engine get build an engine made to rev high, NOT even a 3800."

Admittedly, if you re-cam a 3800 you can make it to rev higher.  whether you would want ot build a 3800 or swap in a front cradle (engine and 4T80 transmission) from an Aurora I am not sure.  The Aurora might be less work on balance but an awful, awful lot of work and you will have to build *that* engine anyway to get hi revs.

Shouldn't need to use a 4T80 trans just to see higher revs. There's more demand to the upper valvetrain of the engine, but RPM presents no additional torque load to the transmission - less in fact for a given power output. Many people don't realize that for a given load, low RPM is more dangerous to a transmission than high RPM, because the clutches tend to slip more. The only real concern you have with higher RPM and an automatic transmission is heat. A $100 transmission cooler and more frequent fluid changes are good insurance.

It might seem counter-intuitive, but one reason I've adjusted my shift points to higher RPM is to decrease stress levels on clutches when shifting. This also lessons the tendency for spark knock (KR) under load, and makes life easier for the crankshaft bearings. This is the same reasoning for leaving the TCC lock-up feature disabled, albeit with some loss to economy on long-distance trips.

AA wrote:

Shouldn't need to use a 4T80 trans just to see higher revs. There's more demand to the upper valvetrain of the engine, but RPM presents no additional torque load to the transmission - less in fact for a given power output. Many people don't realize that for a given load, low RPM is more dangerous to a transmission than high RPM, because the clutches tend to slip more. The only real concern you have with higher RPM and an automatic transmission is heat. A $100 transmission cooler and more frequent fluid changes are good insurance.

It might seem counter-intuitive, but one reason I've adjusted my shift points to higher RPM is to decrease stress levels on clutches when shifting. This also lessons the tendency for spark knock (KR) under load, and makes life easier for the crankshaft bearings. This is the same reasoning for leaving the TCC lock-up feature disabled, albeit with some loss to economy on long-distance trips.

The 4T80 comes with the N* v-8 in the Aurora, that's all... Take the whole cradle - IIRC the  cradle bolts in but the motor/trans mounts and certain other bits differ. You'd want the Aurora PCM too... and the pinouts so you could jumper/connect everything right.  

Would be interesting to set the TCC lockup so it only happens when using cruise control.  You could have your cake and eat it too.

Quote :

Would be interesting to set the TCC lockup so it only happens when using cruise control. You could have your cake and eat it too.

That's how mine is programmed. No lock-up in any gear unless cruise is active.

video from way home. not as bad as it was. im thinkin cats clogged and coils bad maybe?

You mentioned the ignition wires aren't new. I'd get that out of the way before anything else. These should be changed every 100k miles. Recommend using a genuine set of AC Delco/Delphi wires. Good luck.

Ummmmm. Have you bothered to pull codes yet?????  

they where changed with the plugs, cranshaft position sensor, and maf sensor. while i was in north dakota. it still throws the maf code and a "pending" crank sensor code still

P0101, P0102, or P0103??

low 102. yep low input 102 code

Ok.

That means that the PCM is reading less than 1200Hz at idle. If the Crank Sensor and the MAF are new, I'd start looking for vacuum leaks.

 1. Check for the following conditions:
◦Objects blocking the MAF sensor inlet screen.
◦Vacuum leaks around the intake manifold.
◦Vacuum leaks at throttle body.
◦Vacuum leaks at the EGR valve flange and pipes.
◦Crankcase ventilation valve malfunctioning, missing, or incorrectly installed.
◦Low minimum air rate.

The above is directly from my Service Information at work. This is EXACTLY what I'd be doing. If I knew you had access to a good scanner, I think I can copy and paste the entire flow chart for you.

i got the torque app is all
it also has been givin at random a "pending" code cylinder 3 misfire???
i thought cat clogged and or coil bad?

A bad CAT won't set a MAF code.

You need to get that P0303 settled. Check that wire for any carbon tracking or arc marks. If the wires are old, they could be deteriorating and letting the spark through the insulation. However, fixing that misfire won't solve your P0102.

With that MAF code set, the PCM is ignoring the MAF all together and running the engine with calculations based on the IAC position, Throttle Position, RPM's, and MAP sensor (barometric pressure).

A failing Idle Air Control Valve can set a "false" P0102 code. If the pintle inside of it is broken, but the solenoid still works electrically, it won't set an IAC code, but will cause false MAF readings. Especially at idle.....

Will a vac leak cause a stutter at high RPM?

AA wrote:

Will a vac leak cause a stutter at high RPM?

Vac leaks (or restriction) cause all kinds of crap. It just depends on where the vac leak is...before or after the throttle body. Speaking of restrictions....you don't have anything jammed up in the air intake do you?? That would cause a P0102 as well.

His "pending" P0303 certainly isn't helping the situation, and needs to be tended to. I agree 100% that the wires should be replaced. Especially if they're old. The misfire is probably occurring at a certain RPM, and only for a very brief period, which would explain why the code is pending and not a hard set. Bad wires certainly could cause that.

An ignored MAF reading (P0102) isn't going to let the car run properly either...It will throw the fuel trims WAYYY out of whack, and will more than likely cause a stuttering at pretty much any given RPM. It's near impossible for the PCM to run the engine the right way without the MAF.

the wires and plugs are brand new

Ah, ok. I just scrolled up and saw. I missed that earlier...

goin to junk yard tomorrow gonna grab coils, icm, and the wires for as many of the sensors as i can( if not a whole harness) comin from a 2000 regal gs they just got on the lot. hopefully i can track down my prob and fix it this week while im home. also gonna try to find this "T" vacuum conector yall talked about. any pics location info?

joshuadalegrimes wrote:

the wires and plugs are brand new

whose wires?  Some have been bad new.

joshuadalegrimes wrote:

goin to junk yard tomorrow gonna grab coils, icm, and the wires for as many of the sensors as i can( if not a whole harness) comin from a 2000 regal gs they just got on the lot. hopefully i can track down my prob and fix it this week while im home. also gonna try to find this "T" vacuum conector yall talked about. any pics location info?

I am not excited about those Regal wires, I think you will find they changed connectors and/or pinouts on some.

as for the vac, I think vac leak could be a real issue--you should be able to get a replacement vac harness from a dealer for less than $30.-. -- you might should ask. It will have the T and the ends so you don't have any phantom leaks.

got the wires for maf, tps, and the third one that are all together off a 98 park ave ultra, along with the coils and icm, also got the iat sensor and the t vac line setup. put coils and icm on misfire code went bye bye! replaced iat sensor maf code went bye bye. tested and hit wot maf code back. cleared and it only comes back if i hit wot. thats the 102 code. looked on my car for the t vac lines. guess what? my car doesnt have that setup! is that normal?

joshuadalegrimes wrote:

got the wires for maf, tps, and the third one that are all together off a 98 park ave ultra, along with the coils and icm, also got the iat sensor and the t vac line setup. put coils and icm on misfire code went bye bye! replaced iat sensor maf code went bye bye. tested and hit wot maf code back. cleared and it only comes back if i hit wot. thats the 102 code. looked on my car for the t vac lines. guess what? my car doesnt have that setup! is that normal?

get the replacement (I think it is updated) vac harness from a GM dealer not a junkyard. As the rubber ages it develops hairline cracks. So. Get. A. New. One. The vac harness is some nylon tubing with neoprene tees that gets vac from the intake manifold.

as for the 102 code ~~ is your air cleaner clean, did you ever pull the snorkel and check the MAF screen, and did you ever open up the air box and remove that rodent nest from under the air filter (just kidding sort of --no kidding you need to check)