I need HELP!!!!

[jjf76]

I have a 96 Lumina with 181,000 miles on it. Since last summer when I left the car idling for 30 minutes plus I have had this annoying problem where after you run it til it is warmed up and shut it off for 20 minutes to an hour and a half or so it will run horrible.. very rough like it is either flooding or choking itself. If I am fortunate enough to keep it running(while riding the brake and gas pedal at the same time) after a couple of miles it runs fine. If I am not fortunate it will take almost the entire charge of the battery to start if I am lucky. Recently I filled it up with gas at the local gas station just to have it do the same thing but was not able to keep it running and has not started since(2 weeks ago). I have replaced the coolant temp sensor, the PCV valve, the Ignition Control Module, plugs, plug wires, coil packs, fuel filter. HELP!!! Someone else has to have had this or a similar problem. By the way, there is plenty of fuel getting to the engine(you can smell it). HELP!!!!

[PurdueGuy]

getting any check engine codes?

[NOS2006]

Idle Air Control valve? I don't know.

[daves87rs]

Map sensor & EGR.

[NOS2006]

Map sensor & EGR.

EGR came to mind, but why would the MAP sensor be a cause of this? Pressure should be up when it's started, too, and not have to build pressure until at operating temp..?

[76ChevyTrucker]

I would say more along the lines of the Idle Air Control valve due to his saying that he has to ride the brake and the throttle at the same time, which would tell me that the engine is not idling high enough on its own to maintain.

[jjf76]

Actually I have to ride the brakes because if I let the engine rpm go down it starts flooding itself again. And do you mean MAP of MAF sensor and how do you test them or can you? Oh and I forgot to add that the missing/sputtering/flooding, whatever the hell it is has also happened when I got stuck in rush hour traffic in Milwaukee, but not as bad.

Edited May 30, 2006 by jjf76

[CARBIZ]

We have taken in 3-98 Luminas in the past week! The latest one only has 143k km (86k miles) on it. $2,500. Even better - Canadian dollars!

[76ChevyTrucker]

All right, you can test the Mass Air Flow sensor if you have a good DVOM, or preferred an oscilliscope (sp) to watch the pattern, as you increase RPMs, then the voltage signal coming out of hte MAF should increase too. The MAP sensor should work in the opposite fashion. When you accelerate, vacuum pressure decreases therefore the voltage decreases. The reason I say IAC valve is because it is what controls the vehicle idle characteristics (along with information from the Throttle Position Sensor) when you're at idle/low RPM.

[jjf76]

Is it possible the Throttle Position Sensor is shot, because the car is not starting at ALL right now. And when the car was running it would only act like this after you warmed it up, shut it off and let the car sit for 20-90 minutes or so, but yet would run for 650+ miles in one day as long as you didn't let it sit for more than 20 minutes. I have been told multiple things such as Camshaft Sensor, Crankshaft Sensor(and apparently mine has two{7x and 24x}, MAP, MAF, Air Charge) I mean if it is one lousy sensor fine, but if you add the price of all the stupid sensors I might as well replace the engine.

[76ChevyTrucker]

First question. Is the car setting off the "Check Engine" or "Service Engine Soon" light? Second question. If it is, have you run by an AutoZone and had them run the codes on it? Third Question. If you have, can you remember what they are, or at least the DTC (Diagnostic Trouble Code) number, should start with a P-and then a four-digit code, like P0300 (random/multiple misfire detected)? Because without more information I could easily suggest all the above sensors and still not fix the problem without more definite information.

[jjf76]

the only code that ever shows up is Random/multiple cylinder misfire.

[76ChevyTrucker]

All right, what have you done to fix that code? The computer on the cars can actually "prioritize" the codes and will only show one if the ECM deems it as a more important code than others. Which means if you haven't fixed and erased the P0300 code, then that's all that's going to show because the computer see's a random or multiple misfire as a greater evil.

[jjf76]

I have cleared it out multiple times... keeps showing up... why would it tell me random/multiple cylinder misfire... duh OBD-II it's obvious it is misfiring WHY? Sometimes when it was acting up like this I could turn the key to the on position then off then on then off but not to the starting position and when I did turn it to the starting position it would make a more valiant attempt at starting or actually start.

[NOS2006]

TPS could be bad, yeah. My car (before throwing a bearing) had the TPS go bad and it would run about 30 seconds then stall out.. replaced the sensor and it would run (although it had a rod knock).

[Sixty8panther]

Wow... I wish I had something relevant to add. Good luck!

[Buickfosure]

Old century did the same thing replaced coil pack and cam and crank sensors. Its possible its your coil pack.

Sometimes when it was acting up like this I could turn the key to the on position then off then on then off but not to the starting position and when I did turn it to the starting position it would make a more valiant attempt at starting or actually start.

Worked for me also it would sometimes help but hard to tell if it was just a coincidence but man that would give you a little hope you may get it to start without killing your starter and yes I did burn out my starter when I was having the problem. A tip if you live by a junkyard pick up a coil pack for your car beats paying the $99.00 at least for me and it may just fix your problem.. Edited May 31, 2006 by Buickfosure

[jjf76]

Just so you know Buickfosure the ignition control module and the coil packs were both replaced but did the same thing. But you said crankshaft and/or camshaft sensors. And does the 96 3100 v6 have two crankshaft sensors I have seen 7x and 24x sensors advertised, what the hell does that mean?

[76ChevyTrucker]

All right, your car needs too reference signals off the crankshaft so that it can provide an accurate picture of where the piston is so it knows when to fire the spark plugs. The 7x signal is just that, its a reluctance ring in the middle of the crankshaft that the primary crankshaft position sensors reads off of. Its a ring that has a shutter wheel on it with seven teeth, the first six of course are the six cylinders that the car has, then the seventh (actually first), provides a reference signal to let the ECM know that the first cylinder is on its way by. The 24x camshaft position sensor is the one located on a bracket behind the harmonic balancer (crankshaft pulley). That sensor provides a more defined signal that the computer can use to help advance/retard the timing when you stomp on the gas and also helps the vehicle from pinging and detonating.

[jjf76]

So, which one do you think I should replace first? The 7x. the 24x, or the crankshaft? Or should I just do all three and be done with it? Which one might be affected by heat/cool thingy like the original question?

[Buickfosure]

Well its hard to say but I guess if it were me I would go one by one until it works so I might be able to save a buck if I happen to replace the right one before doing all but if cash isn't tight and you don't mind it would save time to do all in one shot. Myself I'm leaning towards camsensor because I was experiencing similar problems and the cam sensor seemed to be the problem but I replced the crank as well because I figured do it now so I'm all set.

Edited June 1, 2006 by Buickfosure