Mechanics

RUNS CHOPPY, FLASHING CHECK ENGINE LIGHT

1996 Saturn SL2

Engine Performance problem
1996 Saturn SL2 4 cyl Front Wheel Drive Automatic 260, 00 miles

car has 260,000 miles on it mostly hwy. Check engine light has been on for a while with two codes for EGR valve and Cat. Conv. Code. But was running fine and getting 30 mpg all the time. Yesterday my husband let the gas tank get a little emptier than I would and filled the tank. It was still fine until later while on the hwy the check engine light started flashing, as getting off hwy it was running realy choppy at lower speeds, fine at hwy speed of 70mph. Took to autoz and had same two codes plus a misfire on #3. At home checked plugs #3 was a little black others all white. Cleaned it also replaced EGR valve, undid battery cables for 1/2 hr like ins. Said to do and tried it again, it was worse. Tried carb cleaner and put in gas treatment but tank is already full, we will replace plugs and wires tonite, do you have any suggestions.
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Twise32
August 27, 2010.




Your on the right tack now. The misfire is the problem you have to get to the bottom of. The plugs and wires are the correct first step.
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Wrenchtech
Aug 27, 2010.
Thanks we will do that as soon as he gets home from work and get back to you with the outcome.

Tiny
Twise32
Aug 27, 2010.
First of all thank you so much for your donation. If your going to replace the plug's and wire's that's great. Just make sure that you don't put in platinum plug's in they don't run long in that model saturn they carbon fowl.I recommend the ngk standard or bosch super standard plug's they run very well in that model. Also when he has the plug wire's off make sure he replaces one wire at time so he doesn't get the routing mixed up. Also have him check the coil tower's for being corroded where the plug wire's go on real common for that model for that to happen. If it's corroded the coil will have to be cleaned or replaced. Sometimes when you clean the tower's it make's the tower too small and the wire won't stay on and click into place so that's another thing to watch out for. So after you replaced the egr you now only have the P0303?If the plug's and wire's don't fix it we will have to dig deeper. Make the spark plug's are gap at.040" some of the emissions label say.060" which was a error. Let me know what you find.

Saturntech9
Aug 27, 2010.
Ok he changed plugs and wires, checked for corrosion on coil (there wasnt any), and it is still running rough. He is taking it back to autozone to have them read the codes again---- any suggestions?

Tiny
Twise32
Aug 27, 2010.
Let's see what codes you have if you still have a p0303 cylinder 3 missifire then I want you to check spark to that cylinder if you have spark then you will have to rent a compression tester and see what the compression is on that cylinder. Let me know what you find.

Saturntech9
Aug 27, 2010.
We have good spark, and can hear the whoosh so we assume we have compresion. My husband and a few friends are thinking we have a fuel injector that is stuck open with some crud from the bottom of the tank, and that is why it runs choppy at an idle or low speeds but does fine at highway speeds. We are going to try to replace the injector for #3 tomarrow am and see what that does for us. Does that sound like it could be the answer?

Tiny
Twise32
Aug 27, 2010.
If you have a miss even caused by low compression it could smooth out when your on the freeway. We can't assume we have good compression without first checking it there is no way to tell from a woosh. Also I would make sure that you have a injector pulse signal to the number 3 injector. If you want to try replacing the injector that's all on you.I would try swapping the number 3 with the number 2 injector and see if the miss goes to the number 2 before I spent the money on a total shot in the dark. Because replacing the injector is a total shot in the dark.I would check compression on all four cylinder's if you rent a compression tester then I will instruct you how to check compression.I would also get a noid light or a test and check the injector pulse. That's where I would go from here. If you want to try swapping the injector with another cylinder then I would try that but I don't recommend just replacing it.

Saturntech9
Aug 27, 2010.
We had a mechanic check the compression---1, 2, 4 were all around 170, but 3 was only around 40. He said he thought it was a valve spring or a bent valve. He pulled off the Valve cover and checked for a broken spring and thats not it. He says he is pretty sure it is a bent valve and that it is about an 8 hr job and labor alone would run about $400. At this point with that many miles on it we are not comfortable with sinking that much money in it. I'm probably better to look for a newer saturn sl. It was the best darn car I've ever owned thats for sure! Thanks for all of your help and the very quick responses were awsome.

Tiny
Twise32
Aug 27, 2010.
Glad to hear you got it figured out sorry to hear that it was bad new's. It is most likely a burnt valve that is what I have seen most often. With that many mile's on it I would put it to rest too.I have 213,000 mile's on my 1999 SL2 and it still run's great. If you have any problem's with the new saturn you get you know how to find us. Thanks for using 2carpros.

Saturntech9
Aug 28, 2010.

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