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Discussion Starter · #1 ·
OK, I've spent hours searching threads before I posted this. Between 1500-1700rpms while lightly on the gas peadal the car feels like it surges or like something is holding it back then letting go. Under any other throttle position or rpm it's perfect. It's a 95ss, cold air and flows, thats it. I've already replaced the fuel filter, treated the gas, checked the egr, replaced the wires and plugs(not fun!) removed and cleaned the throttle body and had the local shop run the codes (no codes showed up) The car runs perfect except for that. I parked it for a week and next thing you know this problem arrises. Any and all help is greatly appreciated.
 

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another possibility is torque converter clutch shudder.
when its surging just push the brake pedal down enough to trigger the brake lights while maintaining same rpm, if surging stops then thats the problem.
nice thing about the transgo shift kit it gets rid of the pwm clutch control which is one of the causes of tc shudder/surging.
 

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Discussion Starter · #6 ·
No deal on engagging the brake. Still does it. I have noticed that its not just at 1500rpm. It's when your foot is just barely on the gas. I also tried replacing the tps. Getting frustrated.
 

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Try this, it worked on mine. It sounds just like my 95 ss, I was calling it a hesitation but.......anyway these are two very easy and free things to try.

  1. First (or second, doesn't matter) clean the mass air flow sensor with alcohol (no not whiskey) rubbing alcohol and a Q tip GENTLY! Actually I used a squirt bottle and light air pressure to dry.
  2. Disconnect the vacuum line to the EGR and plug the line.
This removed all hesitation just off idle on mine. If it doesn't work you haven't lost anything and it only takes minutes. I am not sure which made the most difference. I reconnected the EGR and some of it came back. I disconnected again and it runs great again.
 

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Better than disconnecting the EGR valve is replacing it with an F-body valve. Disconnecting it without reprogramming the PCM may cause other problems. Also, EGR bumps fuel economy and lowers emissions. It's worth keeping.
 

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Discussion Starter · #10 ·
I cleaned the MAF today. Took it out and the same problem. I'm running out of options. I really can't afford to take it to a shop. I'm letting it cool down now then trying to do the egr bypass. Fingers crossed.F***
 

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OK, I've spent hours searching threads before I posted this. Between 1500-1700rpms while lightly on the gas peadal the car feels like it surges or like something is holding it back then letting go. Under any other throttle position or rpm it's perfect. It's a 95ss, cold air and flows, thats it. I've already replaced the fuel filter, treated the gas, checked the egr, replaced the wires and plugs(not fun!) removed and cleaned the throttle body and had the local shop run the codes (no codes showed up) The car runs perfect except for that. I parked it for a week and next thing you know this problem arrises. Any and all help is greatly appreciated.

I've got the same problem... a stuttering/bucking problem when just barely pushing the gas at coasting speed, and one "surge" or almost stall feeling at one position of throttle at first acceleration from a stop, then it takes off with no problem through the rest of the range. Replaced spark plugs, wires, cap and rotor, fuel filter, and air cleaner. No change. I'll be trying some of the suggestions seen in this thread here and will keep an eye on any new developments. Be sure to post if you find something that works. Thanks!
 

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Discussion Starter · #12 ·
Got it! I capped the vacume line at the EGR as suggested(thanks carlrf) the car ran perfect. Gonna purchase a new EGR today. On a side note- whoever designed the ignition system on these cars should be shot. My body is still hurting from doing the plugs and wires! Thanks again for all the help.
 

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Got it! I capped the vacume line at the EGR as suggested(thanks carlrf) the car ran perfect. Gonna purchase a new EGR today. On a side note- whoever designed the ignition system on these cars should be shot. My body is still hurting from doing the plugs and wires! Thanks again for all the help.
Just wait till you have to replace a distributor cap and rotor. Then you will really hate things.cwm5
 

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Got it! I capped the vacume line at the EGR as suggested(thanks carlrf) the car ran perfect. Gonna purchase a new EGR today. On a side note- whoever designed the ignition system on these cars should be shot. My body is still hurting from doing the plugs and wires! Thanks again for all the help.

Cool! I just did the wires on the drivers side and had to quit. Will regroup for the other side, looks harder yet, can't wait. So, I guess the concensus is that I should replace my EGR than just leave it unhooked? Post back on your EGR replacement results.
 

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Cool! I just did the wires on the drivers side and had to quit. Will regroup for the other side, looks harder yet, can't wait. So, I guess the concensus is that I should replace my EGR than just leave it unhooked? Post back on your EGR replacement results.
I went into changing the cap and rotor thinking "this will only take about 20 minutes." Yeah..... NO. I think it took about an hour, 4-5 good deep cuts, and a lot of words that I don't say around my daughter!

My brother and I make the same comment anytime we work on one of our newer cars... If we owned these car companies, we would make it mandatory for a full tune up to be able to be done in less than an hour with no special tools or the engineers/designers would be fired.
This comment was made as we tried to change the 4.3 in my '97 Jimmy and found out we had to un-bolt the body mounts so we could lift the body out of the way of the hanging motor. An 8 hour job became a 4 day fiasco.

I think it has something to do with Unions and keeping the auto worker's pay up over $40/hr.cwm8
 

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Got it! I capped the vacume line at the EGR as suggested(thanks carlrf) the car ran perfect. Gonna purchase a new EGR today. On a side note- whoever designed the ignition system on these cars should be shot. My body is still hurting from doing the plugs and wires! Thanks again for all the help.
An EGR valve can fail in many ways. The carbon deposits can prevent free movement of the plunger. Another possibility is a damaged diaphragm that does not hold vacuum anymore. That last one you can easily test by depressing the diaphragm and plugging up the vacuum outlet with finger. If the diaphragm moves back (even slowly) it is shot. Could you please perform at least that test, so we would know what was wrong with your EGR?
 

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I have found that often the spring in the EGR valve gets weak. It will pass the vacuum test, but still cause off-idle stumble. It's only noticable if you have a new EGR valve to compare it to.
 

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I have found that often the spring in the EGR valve gets weak. It will pass the vacuum test, but still cause off-idle stumble. It's only noticable if you have a new EGR valve to compare it to.
The problem is that you do not really when a NEW EGR valve was manufactured and consequently how weak can be a new spring.
 

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I will have to check the TC by applying the brake like suggested. Im having the same problem, but i believe it is the TC. Thanks
 

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I've had a very similar problem with my '95 9C1. After replacing most of the usual suspect parts and still having the same bucking, stuttering, sputtering problem - running erratically and surging on the 2 4 6 8 bank - I finally found the problem about an hour ago ago.

I pulled the #8 plug wire, popped off the heat shield, put the plug wire back on, made sure it 'clicked' and was properly connected to the spark plug, took it for a ride around the block - and no more stutter, sputter, chitty-bang-bang!

I inspected the inside of the heat shield and noticed a couple mini "arc-and-spark" welds. I decided to insulate the heat shield by coating the inside surface with Permatex Red high temp silicone using an artist brush. I'm letting the heat shield coating dry overnight and will reinstall tomorrow morning to make sure the arcing / shorting problem has been eliminated between the spark plug / plug boot and the heat shield.
 
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