Another "stumble when hot" problem
09-26-2005, 04:59 PM
#1
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Another "stumble when hot" problem
I have done a search for this problem using many different words or combinations of words and I get confused on what could accually go bad "only when hot".
As short as possible, here goes.
I have a 94Z with 95K miles, not a daily driver.
For 6K-8K miles now I have had the problem of my car cutting out when it is hot and only when I try to power-brake it, floor it from a stand still, or at high rpm above 5500.
I bought the car with 24K miles in '97 and the factory opti went out at 33K miles (no, I did not wash the engine) so I know what it feels like when the opti dies. It feels like it, but over 8000 miles I would think this thing would have died already.
About 8,000 miles ago I replaced the plugs (ngktr-55)/wires(taylor 8mm) and even the coil (stock replacement).
I have cleaned the throttle plates with 3M cleaner.
I got side tracked with other bills and now I am back to the car problem.
This past weekend I replaced the 2 original o2 sensors and installed a new fuel filter (they did help with the idle and normal to moderate acceleration).
My main question is, What could make the car do this when hot and do it for so many miles without getting worse or failing?
Opti ?
Fuel Pump?
Fuel Pressure Reg. ?
Idle is smooth as normal so I am not thinking ICM or computer. (?)
I know it has been discussed to death, but please help.
One last thing, I know a guy (not really a friend) that might would check it out on a lap top for me but no sure bet.
As short as possible, here goes.
I have a 94Z with 95K miles, not a daily driver.
For 6K-8K miles now I have had the problem of my car cutting out when it is hot and only when I try to power-brake it, floor it from a stand still, or at high rpm above 5500.
I bought the car with 24K miles in '97 and the factory opti went out at 33K miles (no, I did not wash the engine) so I know what it feels like when the opti dies. It feels like it, but over 8000 miles I would think this thing would have died already.
About 8,000 miles ago I replaced the plugs (ngktr-55)/wires(taylor 8mm) and even the coil (stock replacement).
I have cleaned the throttle plates with 3M cleaner.
I got side tracked with other bills and now I am back to the car problem.
This past weekend I replaced the 2 original o2 sensors and installed a new fuel filter (they did help with the idle and normal to moderate acceleration).
My main question is, What could make the car do this when hot and do it for so many miles without getting worse or failing?
Opti ?
Fuel Pump?
Fuel Pressure Reg. ?
Idle is smooth as normal so I am not thinking ICM or computer. (?)
I know it has been discussed to death, but please help.
One last thing, I know a guy (not really a friend) that might would check it out on a lap top for me but no sure bet.
09-26-2005, 05:10 PM
#2
Registered User
Join Date: May 2004
Location: West Palm Beach Florida
Posts: 938
Re: Another "stumble when hot" problem
Originally Posted by boyd
I have done a search for this problem using many different words or combinations of words and I get confused on what could accually go bad "only when hot".
As short as possible, here goes.
I have a 94Z with 95K miles, not a daily driver.
For 6K-8K miles now I have had the problem of my car cutting out when it is hot and only when I try to power-brake it, floor it from a stand still, or at high rpm above 5500.
I bought the car with 24K miles in '97 and the factory opti went out at 33K miles (no, I did not wash the engine) so I know what it feels like when the opti dies. It feels like it, but over 8000 miles I would think this thing would have died already.
About 8,000 miles ago I replaced the plugs (ngktr-55)/wires(taylor 8mm) and even the coil (stock replacement).
I have cleaned the throttle plates with 3M cleaner.
I got side tracked with other bills and now I am back to the car problem.
This past weekend I replaced the 2 original o2 sensors and installed a new fuel filter (they did help with the idle and normal to moderate acceleration).
My main question is, What could make the car do this when hot and do it for so many miles without getting worse or failing?
Opti ?
Fuel Pump?
Fuel Pressure Reg. ?
Idle is smooth as normal so I am not thinking ICM or computer. (?)
I know it has been discussed to death, but please help.
One last thing, I know a guy (not really a friend) that might would check it out on a lap top for me but no sure bet.
As short as possible, here goes.
I have a 94Z with 95K miles, not a daily driver.
For 6K-8K miles now I have had the problem of my car cutting out when it is hot and only when I try to power-brake it, floor it from a stand still, or at high rpm above 5500.
I bought the car with 24K miles in '97 and the factory opti went out at 33K miles (no, I did not wash the engine) so I know what it feels like when the opti dies. It feels like it, but over 8000 miles I would think this thing would have died already.
About 8,000 miles ago I replaced the plugs (ngktr-55)/wires(taylor 8mm) and even the coil (stock replacement).
I have cleaned the throttle plates with 3M cleaner.
I got side tracked with other bills and now I am back to the car problem.
This past weekend I replaced the 2 original o2 sensors and installed a new fuel filter (they did help with the idle and normal to moderate acceleration).
My main question is, What could make the car do this when hot and do it for so many miles without getting worse or failing?
Opti ?
Fuel Pump?
Fuel Pressure Reg. ?
Idle is smooth as normal so I am not thinking ICM or computer. (?)
I know it has been discussed to death, but please help.
One last thing, I know a guy (not really a friend) that might would check it out on a lap top for me but no sure bet.
Check you taylor wires I have seen post on people having problems with them .
Chris G.
09-26-2005, 05:29 PM
#3
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Re: Another "stumble when hot" problem
Originally Posted by crazypurgatory
Check you taylor wires I have seen post on people having problems with them .
Chris G.
Chris G.
What is the likelyhood of a plug wire being bad when new ?
I guess it could happen but then I would have a mis all the time, right or not.
09-26-2005, 06:00 PM
#5
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Re: Another "stumble when hot" problem
Originally Posted by 1racerdude
Check your plugs and see if the gap has opened up or the end off.
Gap them at .035 before reinstalling to take the load off of the opti.
Gap them at .035 before reinstalling to take the load off of the opti.
09-26-2005, 06:22 PM
#6
Banned
Join Date: May 2003
Location: LA (lower Alabama)
Posts: 6,661
Re: Another "stumble when hot" problem
[QUOTE=boyd]Have not thought of that. I think I gapped them at .050 like I read on the website I ordered them from. [/QUOTE
When an opti gets older and wires too it's harder to fire a .050 gap.
I have said it a thousand times on here that wide gap's don't do anything but sell opti's and tune up's. Wide gaps are good for pollution and if ya run them ya have to stay on top of the tune.
If the plug don't fire it causes the spark to back up in the opti and carbon track the cap and that ruins it.
[/QUOTEWhen an opti gets older and wires too it's harder to fire a .050 gap.
I have said it a thousand times on here that wide gap's don't do anything but sell opti's and tune up's. Wide gaps are good for pollution and if ya run them ya have to stay on top of the tune.
If the plug don't fire it causes the spark to back up in the opti and carbon track the cap and that ruins it.
09-26-2005, 08:20 PM
#7
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Re: Another "stumble when hot" problem
I had another thought.
I don't remember if it was ticking before, or started about the same time, or after my problem began; but I have the infamous ticking that I have seen people posting about on here.
It sounds like a stuck lifter (second cylinder back on driverside) or something to that degree. I have tried Marvel mystery Oil and Seafoam at different times to see if it will help, but it still ticks.
Could it be possible that the knock module ( I have LT4 KM ) is making it do this "cutting out" problem I have?
I have an auto and it does not cut out when I give it enough gas to accelerate around 1200-1500rpms but not downshift (keeping it under a load) .
Does the knock module retard timing when engine is cold (first 15 mins or so)?
I don't remember if it was ticking before, or started about the same time, or after my problem began; but I have the infamous ticking that I have seen people posting about on here.
It sounds like a stuck lifter (second cylinder back on driverside) or something to that degree. I have tried Marvel mystery Oil and Seafoam at different times to see if it will help, but it still ticks.
Could it be possible that the knock module ( I have LT4 KM ) is making it do this "cutting out" problem I have?
I have an auto and it does not cut out when I give it enough gas to accelerate around 1200-1500rpms but not downshift (keeping it under a load) .
Does the knock module retard timing when engine is cold (first 15 mins or so)?
09-26-2005, 08:52 PM
#8
Banned
Join Date: May 2003
Location: LA (lower Alabama)
Posts: 6,661
Re: Another "stumble when hot" problem
Originally Posted by boyd
I had another thought.
I don't remember if it was ticking before, or started about the same time, or after my problem began; but I have the infamous ticking that I have seen people posting about on here.
It sounds like a stuck lifter (second cylinder back on driverside) or something to that degree. I have tried Marvel mystery Oil and Seafoam at different times to see if it will help, but it still ticks.
Could it be possible that the knock module ( I have LT4 KM ) is making it do this "cutting out" problem I have?
I have an auto and it does not cut out when I give it enough gas to accelerate around 1200-1500rpms but not downshift (keeping it under a load) .
Does the knock module retard timing when engine is cold (first 15 mins or so)?
I don't remember if it was ticking before, or started about the same time, or after my problem began; but I have the infamous ticking that I have seen people posting about on here.
It sounds like a stuck lifter (second cylinder back on driverside) or something to that degree. I have tried Marvel mystery Oil and Seafoam at different times to see if it will help, but it still ticks.
Could it be possible that the knock module ( I have LT4 KM ) is making it do this "cutting out" problem I have?
I have an auto and it does not cut out when I give it enough gas to accelerate around 1200-1500rpms but not downshift (keeping it under a load) .
Does the knock module retard timing when engine is cold (first 15 mins or so)?
09-26-2005, 09:10 PM
#9
Registered User
Join Date: Oct 1998
Location: Jackstandican
Posts: 3,144
Re: Another "stumble when hot" problem
Had the same problem. Come to find out the waterpump was leaking via weep hole onto the opti, but only when the cooling system was pressurized.
Put your car on jackstands, start it, let it get up to operating temps and whatch the water pump weep hole.
Put your car on jackstands, start it, let it get up to operating temps and whatch the water pump weep hole.
09-26-2005, 09:28 PM
#10
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Re: Another "stumble when hot" problem
My water pump went out about 30,000 miles ago and I figured it would have effected the opti way before now (aprox.8,000 miles ago).
Besides, how long can an opti fail before it completely fails ?
I am wondering if it is the opti, I just don't want to rush to judgement when it ain't the easiest thing to replace.
Besides, how long can an opti fail before it completely fails ?
I am wondering if it is the opti, I just don't want to rush to judgement when it ain't the easiest thing to replace.
09-26-2005, 09:47 PM
#11
Registered User
Join Date: Oct 1998
Location: Jackstandican
Posts: 3,144
Re: Another "stumble when hot" problem
Originally Posted by boyd
My water pump went out about 30,000 miles ago and I figured it would have effected the opti way before now (aprox.8,000 miles ago).
Besides, how long can an opti fail before it completely fails ?
I am wondering if it is the opti, I just don't want to rush to judgement when it ain't the easiest thing to replace.
Besides, how long can an opti fail before it completely fails ?
I am wondering if it is the opti, I just don't want to rush to judgement when it ain't the easiest thing to replace.
09-26-2005, 09:58 PM
#12
Registered User
Thread Starter
Join Date: Mar 2005
Location: Washington NC
Posts: 42
Re: Another "stumble when hot" problem
Originally Posted by SS RRR
It's an easy check is all...
I just hate to do the opti thing becouse I have said in the past, if I replace my opti, I might as well install a cam and well that leads to rr's and lifters and pushrods and so on... hopeing for easier fix so I can go back to the track now that cooler weather is returning.
Thread
Thread Starter
Forum
Replies
Last Post