RVTRichard

Hello fellow Lumina owners. I’ve had a problem for about 8-months now and still have not figured it out. My Lumina is a 93 with the 3.8 engine and 133,000 on the clock. When the engine is cold it runs super, no problems what so ever. When it has reached optimal operating temperature it sometimes bucks like there’s a midget under the hood pulling off plug wires. This does not happen all the time only once in a while. Enough to give you the fear of being left along side the road. The check engine light works perfectly but does not come on to indicate a problem. In the winter time it runs very well but the warmer the ambient temperature gets, the more frequently it bucks. So far I have replaced all the plugs, ignition wires, MAF sensor, oxygen sensor and have even filled it with high test and you know that hurt and it still acts the same. I have read of similar problems where it was thought that perhaps it could be the TCC solenoid or the vehicle speed switch. Before I go tearing off and putting on more parts I’d like to get someone’s take on this. Any insight is appreciated.
Thank you

discnik

Even though your MIL light is not on does not mean that there cannot be "History Codes" in your computer. With engine running like you describe monitor system should kick some kind of code. I believe Auto Zone ? does scanning. Try this first. Can't Hurt !

RVTRichard

Thanks for the tip but unfortunetly there are not any Auto Zones close by. I have taken it to the local shop and they find no history. And of course the vehicle will not act up when it's there. They also said that the system in place does not give detailed information the way the new computer systems do. They say information from the 93 era is vaque at best.

LMP

Well my '93 just started recently acting in a way that would accept your description..and indeed I will investigate if it is TCC (will install a switch on the wire) , ignition (but I have no codes indeed) or even CV joints...
What surprises me is that it shows even with a very light acceleration and it seems to do it ..or is more perceptible -- with TCC applied in 3 or 4...
If TCC slips, it should throw a code DTC39...but I think all those who have reported a TCC as culprit never told they had a code.. www.avigex.ca/xport/dtc39.jpg says the condition must exist for 10 seconds...but when that happens, the reaction is to ease the throttle...so the 10 sec is never reached...
I'm not in a hurry though..and the problem is not severe..so a lead may take some time to come.

__________________
I don't believe in miracles.

RVTRichard

One more thing that may be of help. When it starts acting up and I take it out of OD and put it in Drive, it stops. It seems that by lowering a gear the problem goes away. Which makes me lean towards a vehicle speed sensor, but who knows?

LMP

One more thought also: this engine runs at such a low RPM that I 'm asking maybe, just maybe, after years and mileage, the transmission pump might not develop enough pressure at 1500 rpm/55 mph in 4thTCC...and either kicking it out of TCC or reverting to 3rd increases the rpm and pump would develop enough pressure to keep all clutches..regardless of which, tight and non slipping....and one thing I'll check very soon it the condition of the transmission filter..that I'm due to change anyway....mmm...for years...sooo....ASA new info comes in, will update.
However though, when it starts acting up, I keep an eye on the tach and there is absolutely not even the smallest sign that the rpm would go up....so, TCC or any other slip does not show at all...

__________________
I don't believe in miracles.

LMP

Well...it is becoming more and more severe...and as it goes, it seems less and less the TCC is at fault. IN fact I'm leaning on ignition problem...and misfires are just much more perceptible when TCC is engaged. One trick I used is to tune the AM radio off station and turn the volume up. We can hear the ignition noise and there is definitely an irregular pattern ..that is changes in the buzz, when it starts acting.
Since I have a CPSensor and ignition module fresh from last year....I'll start with step one: a set of ignition cables....long overdue anyway, then procure replacement coils. WIll keep updating...

__________________
I don't believe in miracles.

RVTRichard

I've allready gone the ignition wire route, along with fresh plugs, MAF sensor and Oxygen sensor. As I wrote before the service light does not come on during these episodes. I am convinced that what ever it is, it's thermal related. It works very well cold and the warmer it gets, the worse it gets. My inspection is coming up soon, I may replace the vehicle speed sensor and see if that makes a difference.

Balloon Man

I have a '95, 3.1 Lumina which seems to have exhibited just about all of the symptoms mentioned in these Lumina threads. Thanks to LMP I have just cured the intermittent wiper problem. I am now interested in this thread as this bucking and poor idle etc. is also happening on my vehicle. I had a tune-up done for me which included wires, plugs, etc. This seemed to cure the problem, (I was congratulating myself for being a clever boy), but now the symptoms have returned. Not knowing anything about "codes" or how to get them, (and the Haynes Manual being of no help), I am flying blind and hoping that one of you posters can help me out. Any feedback as you proceed with your vehicles would be greatly appreciated. It doesn't help that the rear wires are hidden from sight, so that anything which might be visible cannot be seen on this car. Thanks in advance.

__________________
"One thing I know..I wish I knew more"

LMP

DO not loose hope...I'm a little busy at other things right now and I run the Kia Sportage instead since the Transport is almost unserviceable ...still runs but just more than normal throttle brings a lot --A LOT--- of misfire and bucking..whatever the gear..really annoying.
Will update ASAP.

__________________
I don't believe in miracles.

RVTRichard

No problem, next month my inspection for the APV is due. I believe I'm going to have the TCC changed at that time regardless. I hope I have some positive news for you at that time.

Scrapper

have you had the coil pack tested??? on my sons it was 1 of the coils in the pack..you should have 3 in the pack.....good luck.....

RVTRichard

Yes, and they are fine. I truly believe it's the TCC selenoid, everything I have read points to it and I hope I can share some positive results with all of you.

Balloon Man

Thanks for the tip, Scrapper. I'll try check that out tomorrow.

__________________
"One thing I know..I wish I knew more"

LMP

..my next step in line. I have located a complete package (ignition module and 3 coils) for C$85....and at least I will keep it as a spare even if it does not prove the case. I have changed the ignition module itself..just the wafer...last year...so I'd be mad if it had gone wrong in such a short time but all is possible. But indeed I do suspect one of the coils could be the cause here.
By the way, anyone who has changed the spark plug wires, any tiopon how to get this wire holder that seems stuck under the dog bone ?

__________________
I don't believe in miracles.