Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Bad stuttering/hesitation under throttle Out of Ideas, please help!

Thread Tools
 
Search this Thread
 
Old 06-19-2011, 11:49 AM
  #1  
Supreme Member

Thread Starter
iTrader: (4)
 
Ozz1967's Avatar
 
Join Date: Dec 2005
Location: St. Cloud, MN
Posts: 4,780
Received 9 Likes on 8 Posts
Car: 1984 Trans Am
Engine: LS1383 in work
Transmission: Magnum F
Axle/Gears: Zexel Torsen 3.73, 28-spline mosers
Bad stuttering/hesitation under throttle Out of Ideas, please help!

Ok guys, I'm stumped.

84 T/A, CC Qjet, 355. Got the car back from the shop with my rear finally fixed so I'm keeping it under 50mph for the first 200 miles. Installed a set of boot protectors on the drivers side plug wires. Found one wire boot cracked and flaking off. Replaced that wire. All the others looked fine. I have not yet had a chance to pull the passenger side off (Father day BBQ, hope to do it this week sometimes, have to dismantled the AIR hoses to do it).

Anyway, First 60 miles, runs like a champ. Went to get gas today and to put some more miles on it when my problems started. I'm driving on the highway and come into town, as soon as I hit my first stop light, the car starts running a little rough. I switch gears while slowing down and speeding up between the next couple of lights and even at higher RPM's it's stuttering a bit. Finally at one stop light I give it gas and it hesitates (read bogs) and actually dies. I could acutally hear it sigh. Threw it in neutral and it cranked back up but now it's hesitating and really choppy, next to no power. Almost like a misfire or as if it were hitting a rev limiter. Real bad stutter/hesitation. I can actually gibve it gas and the car sort of flat-lines but doesn't die. Had a heck of a time getting up to 40mph. Put it in neutral and it hesitates though 3000rpm then zooms to 6k without much problem. So I'm feathering the throttle until I can get to speed and it starts cutting out, losing power, so I manually change gears trying to get to a different RPM band with no change. Lots of surging though, run smooth for 500rpm, then stutter/hesitate the next 500. Really wierd. Tried it in neutral and it was still cutting out under throttle. Then I'm slowing down and for no reason the car starts revving as if the throttle was stuck. I rev it and pull on the pedal to no avail. I finally turn the key and kill the power when the RPM hit 6500, don't think I broke anything but the car rolled to a stop.

I sit for a moment and then start the car. Starts fine, runs ok, still minor hesitation. Sounds wierd from idle when I give it gas. I really hope I didn't hurt the motor. Anyway, drove off ok, managed to get gas and make the 12 mile trip home at 50mph. Car ran decent with a little hesitation off-idle. Still has power but it seems to me that it's being held back. That's the only way I can describe it...feels like it's running against resistance.

Checked my timing, that's good, (this week will pull passenger side plug wires to make sure they aren't shorting out to the headers like my number 5 plug wire was on the drivers side). Then I checked my dwell on the MCS and I panicked. It's pegged al lthe way to the right on the gauge. I can hear the MCS solenoid clicking but the needle is all the wya right and doesn't move. I tried adjusting the IAC to see if it would do anything but there was no change. Reset it back to where it was.

I just don't know. Dizzy going bad? Bad cap? Obviously I havne't checked the plug wires on the passenger side yet, something else I haven't thought to check? Any help or ideas would be greatly appreciated.

Last edited by Ozz1967; 06-19-2011 at 03:46 PM. Reason: Added/Edited for content
Old 06-20-2011, 03:57 PM
  #2  
Supreme Member

Thread Starter
iTrader: (4)
 
Ozz1967's Avatar
 
Join Date: Dec 2005
Location: St. Cloud, MN
Posts: 4,780
Received 9 Likes on 8 Posts
Car: 1984 Trans Am
Engine: LS1383 in work
Transmission: Magnum F
Axle/Gears: Zexel Torsen 3.73, 28-spline mosers
Re: Bad stuttering/hesitation under throttle Out of Ideas, please help!

Ok, small update. Pulled all of my AIR hoses and stuff out of the way to install the boot protectors on the passenger side. Number 6 plug wire boot was all hard and stiff and severely cracked so bad it fell apart as I was trying to take the boot off. I replaced the wire and installed a boot protector. Hopefully this takes care of at least part of my issues. I'll know more when I drive to work tomorrow.
Old 06-20-2011, 06:09 PM
  #3  
Supreme Member

iTrader: (1)
 
'87IROCZOWNER69's Avatar
 
Join Date: Mar 2010
Location: Goose Creek, SC
Posts: 1,088
Likes: 0
Received 0 Likes on 0 Posts
Car: 1987 IROC-Z and 1988 Iroc-Z
Engine: 5.7 350 V8 and 5.0 305 V8
Transmission: 700R4 Automatic Transmission
Axle/Gears: 3.27 Posi
Re: Bad stuttering/hesitation under throttle Out of Ideas, please help!

Originally Posted by Ozz1967
Ok, small update. Pulled all of my AIR hoses and stuff out of the way to install the boot protectors on the passenger side. Number 6 plug wire boot was all hard and stiff and severely cracked so bad it fell apart as I was trying to take the boot off. I replaced the wire and installed a boot protector. Hopefully this takes care of at least part of my issues. I'll know more when I drive to work tomorrow.
You might as well replace all the wires while your down there if they are falling apart in your hands. Ignoring it will only lead to more problems in the near future. Check your plugs while you are changing out the wires so that you can eliminate more things that could cause problems. Plug wires arent that hard to do (while I do agree the passenger side is harder) you dont need to remove any parts to change the wires (I didnt and I have some pretty thick fingers) all in all it took me like 15 minutes to do one side.
Old 06-21-2011, 12:08 AM
  #4  
Supreme Member

Thread Starter
iTrader: (4)
 
Ozz1967's Avatar
 
Join Date: Dec 2005
Location: St. Cloud, MN
Posts: 4,780
Received 9 Likes on 8 Posts
Car: 1984 Trans Am
Engine: LS1383 in work
Transmission: Magnum F
Axle/Gears: Zexel Torsen 3.73, 28-spline mosers
Re: Bad stuttering/hesitation under throttle Out of Ideas, please help!

Originally Posted by '87IROCZOWNER69
You might as well replace all the wires while your down there if they are falling apart in your hands. Ignoring it will only lead to more problems in the near future. Check your plugs while you are changing out the wires so that you can eliminate more things that could cause problems. Plug wires arent that hard to do (while I do agree the passenger side is harder) you dont need to remove any parts to change the wires (I didnt and I have some pretty thick fingers) all in all it took me like 15 minutes to do one side.
I checked all the others. The only ones on either side that were cracking were the number 3 and 6. ALl the others are in good shape. Must be the heat from the headers because those are the ones that are tucked down in there by all the collector tubes. I didn't have time to check the plugs. Two kids and a wife who doesn't understand the need to check all this stuff means my time is limited to an hour here and there. Besides, on the passenger side, I had to remove all of the smog stuff just to get to the plugs, then jack up the car to get to the number 8 plug. Ick...i hate that one.
Old 06-21-2011, 12:18 AM
  #5  
Supreme Member

iTrader: (1)
 
'87IROCZOWNER69's Avatar
 
Join Date: Mar 2010
Location: Goose Creek, SC
Posts: 1,088
Likes: 0
Received 0 Likes on 0 Posts
Car: 1987 IROC-Z and 1988 Iroc-Z
Engine: 5.7 350 V8 and 5.0 305 V8
Transmission: 700R4 Automatic Transmission
Axle/Gears: 3.27 Posi
Re: Bad stuttering/hesitation under throttle Out of Ideas, please help!

Originally Posted by Ozz1967
I checked all the others. The only ones on either side that were cracking were the number 3 and 6. ALl the others are in good shape. Must be the heat from the headers because those are the ones that are tucked down in there by all the collector tubes. I didn't have time to check the plugs. Two kids and a wife who doesn't understand the need to check all this stuff means my time is limited to an hour here and there. Besides, on the passenger side, I had to remove all of the smog stuff just to get to the plugs, then jack up the car to get to the number 8 plug. Ick...i hate that one.
Wierd, me and my neighbor got it all done in a few hours with no removing of parts. We still had to jack up the car to do half the plugs but he would work from the top and I worked from the bottom and we worked like a poorly lubricated machine! lol Sounds like you need to get a buddy to help you and reward him with some beers (or do you call it lager in the UK?).
Old 06-21-2011, 12:47 AM
  #6  
Member
 
camaroinoh's Avatar
 
Join Date: Sep 2010
Location: NE Ohio
Posts: 113
Likes: 0
Received 0 Likes on 0 Posts
Car: 84 z28
Engine: 305 for now, lil more then stock
Transmission: 700r4 for now
Re: Bad stuttering/hesitation under throttle Out of Ideas, please help!

Could be back pressure hows the cat
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
pimp2303
TBI
7
07-27-2017 02:03 PM
GouldyGTR
DFI and ECM
3
08-21-2015 10:43 PM
mdtoren
Tech / General Engine
0
08-16-2015 05:45 PM
perZ
TPI
7
08-15-2015 01:17 PM



Quick Reply: Bad stuttering/hesitation under throttle Out of Ideas, please help!



All times are GMT -5. The time now is 02:51 PM.