3800Pro Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter #1
I have a '97 LeSabre with 190k miles. Drove it 100 miles yesterday and several times there and back I had a jerk like it was missing but no codes.

What is the best way to narrow down transaxle vs. engine problems?

I have not replaced the transaxle fluid (ever, but it looks okay), and this is a problem that just showed up out of the blue. If I had to guess at this moment, I'd say it is a sensor or electrical connection.

Any advice is welcome.
 

·
Registered
Joined
·
233 Posts
That's an extremely vague description, and you're going to be guessing non-stop without actually scanning it and/or getting a trusted mechanic to evaluate it, if it's enough of an issue affecting drive-ability.

Could be a million things based on what you said: engine missing due to bad gas, clogged air filter, dirty/faulty MAF, vac leak from part/hose/connector, error from spark plugs/ignition, wiring harness break/bad ground... or transmission/torque converter from a variety of issues that requires an even better technician to diagnose/rebuild.

Hopefully, it's something simple, but troubleshooting is a process based on getting as much accurate and precise information as possible (speed, timing advance, temps, throttle position, trans settings, etc. can all be scanned to show the full picture, some do this with the Snap-on tool, while enthusiasts have things like our tuning programs).
 

·
Registered
Joined
·
31 Posts
Discussion Starter #3
That's an extremely vague description, and you're going to be guessing non-stop without actually scanning it and/or getting a trusted mechanic to evaluate it, if it's enough of an issue affecting drive-ability.

Could be a million things based on what you said: engine missing due to bad gas, clogged air filter, dirty/faulty MAF, vac leak from part/hose/connector, error from spark plugs/ignition, wiring harness break/bad ground... or transmission/torque converter from a variety of issues that requires an even better technician to diagnose/rebuild.

Hopefully, it's something simple, but troubleshooting is a process based on getting as much accurate and precise information as possible (speed, timing advance, temps, throttle position, trans settings, etc. can all be scanned to show the full picture, some do this with the Snap-on tool, while enthusiasts have things like our tuning programs).
Thanks for the response. I need to get it back out and do more tests. I've been working and didn't want to drive it out of town the past 2 days.

I have a cheap scanner and I will get more data. I was more interested if the transaxle starts going bad all of the sudden what happens. I've never had one go bad before.
 

·
Registered
Joined
·
892 Posts
I second that last reply. You could go thru a lot of parts or guessing which may get expensive. Get the car hooked up to a DIAGNOSTIC SCANNER and watch the SCAN DATA to see what is happening when the condition occurs. On another note, it could be a MISSFIRE that acts up under load or when everything id heated up. You could guess at several things but that can get more expensive than a good scan diagnostic. GOOD LUCK.....Mr Goodwrench jake
 

·
Registered
Joined
·
31 Posts
Discussion Starter #5
I second that last reply. You could go thru a lot of parts or guessing which may get expensive. Get the car hooked up to a DIAGNOSTIC SCANNER and watch the SCAN DATA to see what is happening when the condition occurs. On another note, it could be a MISSFIRE that acts up under load or when everything id heated up. You could guess at several things but that can get more expensive than a good scan diagnostic. GOOD LUCK.....Mr Goodwrench jake
Hey Jake, thanks for weighing in. I have more info after finally having a little time to check it out.

I started it today and tried to back out of the garage, but it acted like the brakes were stuck or the trans was broken. It still ran though and finally managed to limp back several feet but I put it forward back in the garage with it stuttering and sounding like a misfire.

I had to run an errand then came back to dig into it. It started and idled fine. Once I put it in reverse, it would idle but start misfiring. Neutral was fine, drive would misfire.

I backed it out of the garage running fairly well, then drove around the block with zero problems so I parked it.

No MIL but I pulled out the scanner and saw a PO306 and PO401. Cylinder 6 misfire and EGR, which I replaced late last year.

Tomorrow I will do a visual check of the 6 plug, wire and coil connection. Also will check the EGR connections and may run a wire brush down in the EGR pipe.

At least I have a starting point now..
 

·
Registered
Joined
·
233 Posts
Might point to the source of a vacuum leak. EGR is a joke in the 1st place, siphoning fumes only from #6 exhaust manifold during certain conditions. You can delete it, partially (capping exhaust manifold & letting EGR draw clean air-only) or fully delete (capping exhaust and intake ports and removing, or leaving on while tubing hangs free), to eliminate that as a potential issue. I would check the metal tubing for cracks, as well.

It sounds like your engine has a serious issue trying to get the right air-fuel ratio under most conditions. If nothing jumps out at you under the next couple looks, I would bring in some hired help.
 

·
Registered
Joined
·
31 Posts
Discussion Starter #7
Might point to the source of a vacuum leak. EGR is a joke in the 1st place, siphoning fumes only from #6 exhaust manifold during certain conditions. You can delete it, partially (capping exhaust manifold & letting EGR draw clean air-only) or fully delete (capping exhaust and intake ports and removing, or leaving on while tubing hangs free), to eliminate that as a potential issue. I would check the metal tubing for cracks, as well.

It sounds like your engine has a serious issue trying to get the right air-fuel ratio under most conditions. If nothing jumps out at you under the next couple looks, I would bring in some hired help.
Thanks Dave, you are always a big help in this forum.

This car has been running great until the last trip I took, then started missing out of nowhere.

I will respond when I have another chance to dig into it.
 

·
Registered
Joined
·
892 Posts
Thanks Dave, you are always a big help in this forum.

This car has been running great until the last trip I took, then started missing out of nowhere.

I will respond when I have another chance to dig into it.
I removed the EGR on my GTP and made a BLOCK OFF PLATE to cover the EGR holes. Haven't looked back since...runs good with no issues........ Jake (goodwrench)
 

·
Registered
Joined
·
31 Posts
Discussion Starter #9
Problem found. Arcing at the #6 coil carbonizing the wire boot. Looks like caused by a rusty coil connector. Cleaned and crimped to verify a smooth idle.

I threw on an old EGR I had sitting around. I don't have the tool or money to flash the PCM right now.

New set of wires on the way and I'll clean all the coil connectors and use dielectric grease to avoid future rust.
 

·
Registered
Joined
·
233 Posts
Hope that takes care of it. (y)
 
1 - 10 of 10 Posts
Top