[MysticMoonflower]

No check engine light but whenever I accelerate on the road normally or at higher speeds (70-90 mph) it shudders like a misfire. Just recently replaced spark plugs 8,000 miles ago at 60,000 miles. Just replaced the battery a month ago and an oil change a week ago but my mechanic can't find anything because of there being no check light or codes popping up.
Any suggestions on how to diagnose it and fix the problem before it becomes something worse?

Thanks

 

[RSR]

No check engine light but whenever I accelerate on the road normally or at higher speeds (70-90 mph) it shudders like a misfire. Just recently replaced spark plugs 8,000 miles ago at 60,000 miles. Just replaced the battery a month ago and an oil change a week ago but my mechanic can't find anything because of there being no check light or codes popping up.
Any suggestions on how to diagnose it and fix the problem before it becomes something worse?

Thanks

When mine does that its usually because my Stabilitrak system is about to fault. You could have that checked if you wanted. My Stabilitrak is terrible so it may not be your problem. It could also be in the injectors. They could be bad or dirty. Try getting some top end cleaner that mixes in with the gas. I've had good success with the Lucas oil ones. I like the deep clean one the best. But the smaller bottle of injectors cleaner is good too.

 

[Traxy]

I use the one GM recommends about twice a year, it's due now because when I'm at cruising speed I can feel some sputter every once in a while so I no it needs a good cleaning. This usually works within a couple of hundred kilometers after treatment.

 

[Led]

I have a single cam Saturn SL1.........
Even brand new......I went all the way out West to Wyoming through South Dakota.......with it to the floor. Me and the Wife, luggage and the air on. Top speed? 80mph.

You may be expecting WAY too much out of such a small engine. Hitting the rev limiter much?

Move up to a V8????

 

[larrywhart2010]

The spark plug contacts in the spark plug boot may need to be replaced. I just replaced all four boots on my Trax.