Here's my symptoms, what's the diagnosis?

[scansinboy]

Here's what my car (91 Saturn SL, manual, SOHC, 180k) has been doing for the last few weeks.

Ill be driving along the freeway and suddenly there will be a loss of power in the engine, but not a loss of rpms, and then it will kick back in. At slower speeds, the engine will konk out, rpms dropping to 0, but then I can restart the engine, and keep going, so it's not the battery or the ignition. Sometimes it's bad and I have to start the engine 4 times or more to get out the driveway. At first I was thinking it was a clogged fuel line or fuel pump or impurities in the gas or something, but here's the wierd part. I'll rev the engine up to about 4 or 5k rpms for a few seconds and then it acts fine, except then, when I press the clutch in, it actually idles higher, around 2.5k rpms. So now i'm thinking it might be something to do with the throttle(?) or whatever makes the car idle at a certain speed. (Something sticky?) Anyone have any ideas? I'd like to narrow down the problem before I take it in so the mechanic has at least some idea of where to start.

[MSD]

Sounds like the fuel system is losing pressure. I'd get the fuel pump tested ASAP. If that checks out fine, and you don't have any noticeable leaks, it's probably bad injectors. The reason it revs higher when you push the clutch is that, when it's idling in neutral, it's still turning the internals of the transmission. One of my friends noticed that his revs drop about 80-100 when he turns the rear defrost on because of the extra drain on the electrical system. I notice the same (although no tach) when I push all 4 window switches at once.

[Peryn]

While it shouldn't make that big of a difference, do you have the A/C going? As the AC kicks on and off, you will often see a noticable difference in power. I would definately get the fuel system tested, but you will want to get a fuel induciton service for sure. With that kind of mileage, it could make a big difference. If you are at all mechanically inclined, id recommend cleaning the throttle body yourself. As gunk builds up in there, the throttle plate can stick, open or closed, giving you a high, or low idle. I know on my jeep they were constantly haveing recalls and TSBs about the trottle cable itself getting stuck and causing a high idle.

Now, does it ever die on you while your foot is on teh gas, or only while off the throttle?

[Ilow]

I know on Volvos that there is a Constant Idle Speed sensor which can occasionally go bad. This would explain many of your symptoms if indeed your vehicle has a similar device.

[2sheds]

my f150 had a similar problem that turned out to be a problem with the "idle air control valve" sticking. it was about a $70 part and easy to replace myself.

dunno about saturns, though...

[Sion]

ever had the catalytic converter replaced?

[scansinboy]

I replaced the catalytic converter about a year ago, I'm pretty sure that that has nothing to do with the problem.

[krwlz]

After replacing a fuel pump on a saturn, I'd get all that checked out.

[dpezzo]

is there a way to test if a catalytic converter needs replaced, or do you simply have to replace it to see if it fixes the problem? I have an intermittent power loss issue with my car (2001 malibu), and someone told me had to replace the catalytic converter on his car to fix the problem.

[Turbotom]

I would guess that it's either the mass airflow sensor (assuming it has one,) a map sensor (in case it doesn't use a MAF,) or the idle air controller. It could be the fuel pump, if you have a fuel pressure gage you could easily connect to the fuel rail, it'd be worth checking.
Another thing that happens with older GMs is the coolent sensors tend to break. Does your coolent light ever come on when the coolent level is fine?
Sensors tend to act randomly, and that would explain random times that it has issues...

[laconic1]

A catalytic converter seems like an odd candidate for an intermittent power loss problem. Usually when a converter fails the power loss is there all the time since it is usually plugged. Or when the material in the converter breaks down a code will be set for catalyst efficiency. Depending on how random it is I agree that a sensor is more likely for an intermittent problem.

[DEI37]

Yeah, I can agree that the fuel system is the culprit here. Fuel pumps can cause intermittent problems similiar to what you're describing. Been there, done that. Good luck.

[TM875]

My first thought is that it's a Saturn with 180K miles on it. That should be the cause of most of your problems...

[mazak]

My first thought is that it's a Saturn with 180K miles on it. That should be the cause of most of your problems...

thank you for you're help!

im leaning to fuel related is the check engine light on? has it been on? does it work?[bad bulb]

[crxforum]

It could very well me that your O2 sensor is gone. Ive had a few O2 sensors go in my day and they are very close to the symptoms that you are describing. You might also want to check the main fuel relay, injectors, fuel pump, fuel filter, and even the distribuator. They could all be causing this problem. Do you know if your car is OBD0, OBD1, or OBD2? If you have an OBD0 you can just check your ECU and see what the code is. If OBD1 then you can get a cheap ass plug in scanner for like $30 at Pep Boys to check out what the problem is.

CRX Forum

[mazak]

hi,91,is obd1,here is a link that will explain how to retreive the codes,if any are stored. good luck !!

http://www.troublecodes.net/saturn/

[merkerguitars]

Go to your local autoparts store, most of them have OBD1 and OBD2 scanner that you can rent for free. If a code doesn't show up I would almost assume its dirty fuel injectors.

[mazak]

well.scansinboy,have you done any thing? an update if you please? and most major auto parts stores will read the codes for free.no code reader rental,free. good luck man,and please let us know??????