'98 SW Jerk/Stutters

[skyrat]

Hi all,

Absolutely great and helpful forums, wow.

I've got a '98 SW1 (automatic, 91k miles) that recently developed a problem on a LONG roadtrip (20hrs continuous driving).

At the very end of the trip, just off the interstate, I noticed the car jerks/hesitates when accelerating. There were not noticeable problems to begin with while crusing at a relatively 70MPH. The problem has continued to get worse and seems to only start to happen once the car is warmed up.

Symptoms:

• Mild to medium acceleration, car jerks/stutters
• Step on it hard, problem seems to go away or is reduced
• Idles / starts just fine
• Once up to speed and crusing, smooth sailing
• Heading up a long incline, if trying to maintain speed, car will begin same jerk/stutter routine
• No lights on/tripped
• Not a function of traction control, when turned off, problem still exists
• When cold, problem less pronounced
• Has gotten worse as time progresses
• Happens in any gear

Other than the problem described, the only issues with the car is eating oil, which is has been doing for some time now, and in my experience, is a defacto standard of all the 4cyl saturns I have owned.

Thoughts / suggestions?

[skyrat]

Forgot to add, no change in mileage noticeable. I'm getting similar mileage to what I normally get (even got 35.6MPG during one leg of the long drive).

[fdryer]

Welcome to Saturnfans! Nice post, putting all essential information up front. Newbies take notes!

You may have a problem with the electric egr valve sticking, on the right side of the engine under the air intake tube. A quick test would be to disable it by disconnecting the wiring plug to it and driving. Ignore the SES light for now. Normally the engine doesn't need/use the egr at idle so cold starting and warm up should be fine but if there's any stalling or hesitation, the egr valve may be sticking open and allowing exhaust gas into the fresh air intake system to interfere with engine running. As it only operates above idle speed your idle should be normal. If its sticking during driving it can create what you're describing so disconnecting it would be a simple way to eliminate it. The egr valve should stay closed and is closed at idle speed when you disconnect the plug. If driving goes back to normal then the egr valve needs cleaning. Look in the How-to library for cleaning tips otherwise you may have to replace it. If this doesn't work, re-connect the plug and move on with more troubleshooting. Done any tune-ups or maintenance?

[skyrat]

Forgot to add, which might be important, the car does not exibit this behavior when in neutral and I step on the accelerator.

I'm going to try pulling the EGR shortly.

[skyrat]

Update:

Didn't get to disconnecting the EGR. I first checked the spark plug wires and I discovered there was a whole mess of oil in the left most plug. I took the plug out, cleaned it, put it back in, cleaned the wires, plugged it back up. Started the car (huge plume of smoke came out the exhaust) and test drove around the block a few times until it warmed up. No obvious jerking. . .

Is this a sign there is a crack in the block some where? How'ed that much oil get there.

[fdryer]

Cam cover leak, that's all. The gasket or RTV just wears out and allows oil to pool eventually breakng down the high voltage insulation. Spark just grounds through the engine block instead of across the plug gap. You'll probably have to remove, clean, and re-seal the cam cover with a gasket kit.

[2NDSOUT]

May I suggest too that maybe the Spark Plugs may be bad?

How recently were the wires and plugs themselves changed? If you are over 30K miles since the last time plugs and wires were changed, it may be time.

I had a similar issue in my 94 SC1. Turns out that my Spark plugs had wiggled themselves loose. Since they were loose, I was going through a bit more oil than usual and my plugs got burned up real quick.

Make sure that all of your connections on your plugs and wires are good, clean and tight.

Checking the EGR is a good suggestion too from FDryer. In 90% of most misfires/Jerking/Stuttering, it's probably the EGR or the Plugs that are in need of some work.

[skyrat]

I recently inherited the car and know for a fact it was not taken care of as well as it should have been. The plugs/wires should probably be replaced.

Any danger in cleaning the EGR valve as preventative maintenance if it is currently not causing a problem? I'd assume that given the fact that these engines burn oil, the EGR would more often than not eventually need attention.

[OldNuc]

The only drawback is you will need a new gasket. A preventive maintenance cleaning will not hurt anything. A good idea actually.

[BarnOwl]

Originally Posted by OldNuc

The only drawback is you will need a new gasket. A preventive maintenance cleaning will not hurt anything. A good idea actually.

Most of the time you can reuse the EGR gasket if it doesn't tear. Of course, if you don't have a spare on hand, it'll tear for sure. It's around $2.

[OldNuc]

That is why as soon as you have an entire spare car, all in loose parts, it never brakes again.

Dose not work if the spare is assembled.

[pthoracek]

I'm having the EXACT SAME problem with my '97 SL2, and its been perplexing. It feels like a fueling problem. It only happens when the engine is under load. It stutters from about 2K RPM up. Sometimes, when you give it more throttle, it picks up. Sometimes it flatspots and won't go above 3K RPM.

Changing the fuel pump and fuel filter/regulator didn't help. I replaced the plugs and ignition wires. No joy. I tried the EGR test outlined for you, but the problem occurs even when the EGR is disconnected. I cleaned the EGR. This resulted in an almost 2 MPG boost, but didn't clear the trouble. The O2 sensors are both new. I've cleaned the ignition module and the coil packs. Haven't had a chance to swap them out yet though. I've been told that a clogged catalytic converter or muffler willcause this, but I would think that it would show up to some extent when revving the engine in neutral. I hate this easter-egging. I hope you have beeter luck!

Pete

[OldNuc]

This is the cheap easter egg test. Remove EGR and cut up a piece of adult beverage can of your choice that will cover both ports on the EGR with as much overlap as you can manage without making a new gasket without holes. Lay it on your gasket and put the EGR on top of it. Plug in the EGR. You will get an EGR code eventually but that is not the purpose of this exercise. Drive the car and see if the problem has gone away. Driver it for several days to be sure its OK.

This also might be part of your problem. Check that the port under the MAP sensor that leads to the intake is clear of any crud that might block it. Also check the rubber seal on the bottom of the MAP sensor and look at the little port and verify that its clean. Do not try and blow it out, that will rupture the MAP diaphragm and then it will be broke. If its dirty/plugged you might manage to get it clean with a tooth pick but don't poke it in too far.