Lurching, leaping, bucking?

[jon]

Have lurching, leaping, bucking issues; some at lower speeds but particularly noticeable in the 65-75 range. Car surges up and down as though on a road with dips. Almost feels like when one hit resume on cruise but problem is I don't have cruise on??Have had it in garage for over a week and they cannot id? Nothing shows on their systems. Any one had a similar problem? Thank you and glad you are all here.

[scottydl]

jon said:

Have had it in garage for over a week and they cannot id? Nothing shows on their systems.

This is quite annoying, that mechanics nowadays are practically useless unless the computer tells them what to fix. (Sorry for the mini-rant.)

Anyway, what is the mileage on your Aurora? This sounds almost like a tune-up issue, although I'm guessing your miles are low (within warranty range anyway) if you're taking it to the shop right away. With most Auroras, we'd generally suggest new plugs & wires first to see what happens... but usually miles are high before these problems pop up.

[Marc]

My guesses: fuel filter, fuel pressure regulator, fuel pump.

[jon]

Thanks Scotty and Marc...........this whole deal is frustrating. I have just short of 60,000 miles. Mechanics go by their equipment only, it seems to me, as you suggest. I started racing cars in 1960's and we did it more by feel, ear, feeler guage, etc.........when I suggested plugs, answer was: " no, the book says the plugs are good until 100,000........." Well hopefully they pulled nonetheless and looked for a porcelain crack, carbon, etc...........and same with wiring.........pretty simple to change out. However, in their defense they say they when the computer does not read out a problem there bosses don't like them spending money trying this and that. I may be stuck with this surging issue.............again very frustrated. Thanks again.

[Wacko]

What year? Can you elaborate on the symptoms? Are you sure it is the engine and not the transmission or torque converter? Have the mechanics considered the transmission might be faltering?

[jon]

Wacko - it's an 01 and all good points. Thanks. So far, and I still don't have it back, they have replaced out the fuel filter and flushed the injectors, if I have not mentioned..........still the surge. As others have suggested, I hope they will now check the plugs/plug wires, fuel pump, fuel regulator, etc..........they keep coming back with the problem of nothing showing on their computers. Very frustrating. Had another 01 prior and regretted I ever let it go, so hope I can work this out. Never had a car which seems to defy fix.

[jon]

Symptoms by the way are going down interstate without cruise on but it feels like some one is kicking in resume repeatedly so there is a constant up and down surgurge of the engine.

[Wacko]

Under 60K. Me, too.

Hard to tell from here (I'm leaning towards transmission) but you might check out reply #13 in this thread and compare symptoms.
aurorah.proboards47.com/index.cgi?action=display&board=Gen&thread=1137117447&page=1

First step I would do would be to check the transmission fluid level and condition (color, smell, cloudy, clear, etc.) This is done on a warmed up car with the car running and in Park.

[jon]

Thanks Wacko........I will definitely check out. I'm blessed to have an Aurora again and bound to get to the bottom of it. They kept if over the weekend and are now thinking it's plug wires as one of our prior site colleagues suggested early on. I will also visit # 13 as you suggest, too.......ironic as today is 13th. ha. TGIF and have a good one. Much appreciated. Will let you know when they do pin down the problem.

[jon]

what does # 13 on this thread mean. I counted down to 13 and found it to be a coolant issue. Sorry for the dumbness on my part, new here.............

[Wacko]

Sorry. Each reply to the original post has a number like:

Re: Entering the Home Stretch
« Reply #13 on Today at 2:31pm »

[jon]

Thanks Wacko

[Wacko]

One other thing to check. Do you have any problems with twiching in your foot? This might explain the sudden acceleration, etc. Just trying to lighten up the mood here. Both the Patriots and the Bruins lost yesterday. I'm going to go make a sandwich.

[Aurora40]

jon said:

Thanks Wacko........I will definitely check out. I'm blessed to have an Aurora again and bound to get to the bottom of it. They kept if over the weekend and are now thinking it's plug wires as one of our prior site colleagues suggested early on. I will also visit # 13 as you suggest, too.......ironic as today is 13th. ha. TGIF and have a good one. Much appreciated. Will let you know when they do pin down the problem.

The wires are super short on these cars, and contained in the head. So there isnt' too much that can wear them out like exhaust pipes and physical abrasion. Still worth checking, though. But it sounds to me like you might need to be monitoring what is going on while it is happening. It could be all kinds of random things, torque convertor locking and unlocking, fuel pressure variations, the car cutting out fuel thinking you let off the gas, who knows.

[jon]

Foot my eye. I see where you got the name Wacko , ha. Gotcha back. Yeah I wish it was me........ha...
Guess they may move now into condenser, coil?? Perhaps Aurora 40's idea of checking while moving is best..............it's become a real puzzle. I still think it's injectors but they don't want to step up to the cost. That's my bet. They say they flushed them but still think that's the source. I had a Pont Grand Prix, super charged, quite a few years ago, and it was kind of acting up similarly and I hate to simply pay the piper...we shall see. Thanks all.

[Wacko]

Maybe this will help.

aurorah.proboards47.com/index.cgi?board=1stgen&action=display&thread=1098601197

[jon]

Still can't fix my 2001, 4.0...........they do have a 4.0, 1998 very nice with only 66,000 miles. Thoughts from any one? Would I be making a mistake to move down to 98? I really like the looks of the 1st gen......
Thanks alot

[Wacko]

Personally, I don't yet believe your 2001 is hopeless.

I'm sure your mechanic checked all of the below steps which are recommended with a surge or chuggle condition but no codes are set. But just to be sure, I would suggest you verify each.

* Visually check vacuum hoses for splits, kinks and proper connections as shown on Vehicle Emission Control Information label.
* Ensure Park/Neutral Position (PNP) switch is properly adjusted.
* Check for intermittent open or short to ground in Torque Converter Clutch (TCC) or HEI by-pass circuits.
* Check canister purge system for proper operation.
* Check ignition control system for proper operation.
* Check EGR system for proper operation.
* Ensure initial ignition timing is correct (4.9L HEI only).
* Ensure the installed PROM is correct for that particular vehicle. Check with dealer for latest application information.
* Check for adequate ignition voltage output using Spark Tester.
* Check oxygen sensor for contamination. This will cause a false high voltage signal to PCM. PCM will respond by leaning air/fuel ratio.
* Check in-line fuel filter, and replace if dirty or clogged.
* Check fuel pressure while condition exists.
* Check for poor quality or water contaminated fuel.
* Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits. Also, check condition of distributor cap, rotor and spark plug wires.
* Check charging system output. Repair charging system if voltage is less than 9 volts or more than 17 volts.
* Check A/C for excessive charge.
* Check for restricted exhaust system.
* Check injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.
* Ensure driver understands operation of TCC and A/C. See owner's manual.
* Check speedometer calibration.
* Check for rich or lean conditions. Drive vehicle at speed when complaint occurs.
* Check for plugged injectors. Perform INJECTOR BALANCE TEST

See www.v8mr2.com/reference/Tests_without_codes.pdf for the complete reference. Granted this is for 1995 Northstar-based Cadillacs but since you have no codes, I'm thinking it is applicable.

[jon]

Wacko - can't tell you how much I appreciate your help.......such great detail and awesome effort on your part. I have already passed on your ideas by v/mail to the service mgr. I can recall most all the above having been addressed but a few listed I have NOT heard him address. In the end, it could prove to be invaluable. Thanks again. I sure hate to give up my 2001........but I would have difficulties living with the present symptoms...........have talked to a couple of mechanics familiar with Olds in my area.......and they recommend keeping the 01 if at all possible. Have a nice evening......I owe you much.

[Wacko]

Jon,

Well, I feel I may be bordering on information overload, but I am truly trying to help out. It is difficult to diagnose something based on a description of symptoms only. Also, in this case, we don't know any history of the car since you just purchased it (correct?). I try to provide relevent info without overwelming.

The tendency by some (myself included) is to recommend swapping out parts blindly. This can get expensive and time consuming.

I am not a mechanic, but I did stay at a Holiday Inn Express...

Seriously though, there are many things that can cause the symptoms you describe. Everything from water in the fuel rail to the TCC engaging and disengaging. If you are prepared for the challenge of diagnosing this, you will need to divide and conquer the list.

Good luck whatever you choose to do.

Paul

[jon]

Thank you again, Paul. Much appreciated...........certainly insightful tips...........I will keep you posted. I hope they can get to the bottom of it. I love the car...........

Jon