1999 SL 1 “jerky” under load --EGR valve?

[notmycity]

1999 SL 1 “jerky” under load EGR valve?


1999 SL 1 “jerky” under load about 45-50mph. EGR valve?

We’re also getting a pretty noticeable clunk from the tranny while shifting when it’s cold, usually under 35 mph.

Any thoughts appreciated.

Thanks.

[Bob K]

Sure. EGR valve is possible. I had the same issue with my '93 SC2 at 35-45 mph. Kind of a miss that went away at lower or higher speeds.

Your transmission may need a new valve body. Just do a search for "valve body" or "reverse slam" and prepare for some heavy reading.

[OldNuc]

First, replace the ECTS if you have not done so already. Next perform a test of the EGR. Cut a piece of can that will cover both ports completely under the EGR valve. Put the can piece under the gasket and reinstall the EGR, plug it back in. Now go drive the car and see if it runs better. You will eventually get a code from having the valve blocked off, it takes a while. You can run this way for a day or so but then remove the can. If the car runs better with the EGR blocked then the EGR is in need of a serious cleaning.

[rc1488]

Change your tranny fliud and filter. Should be changed every 20k at least.

A fualty or dirty EGR often cuases issues at constant speeds, not under acceleration as much.

[JerryHughes]

Originally Posted by rc1488

Change your tranny fliud and filter. Should be changed every 20k at least.

A fualty or dirty EGR often cuases issues at constant speeds, not under acceleration as much.

Not in my case. I followed Old Nuc's recommendation about blocking off the EGR and my hesitation stopped. So I replaced the EGR. Problem solved. But, in my case, the only way I could tell the EGR was bad, was when I was accelerating. Upon acceleration, I experienced hesitation---none at constant speed.

[rc1488]

Originally Posted by JerryHughes

Not in my case. I followed Old Nuc's recommendation about blocking off the EGR and my hesitation stopped. So I replaced the EGR. Problem solved. But, in my case, the only way I could tell the EGR was bad, was when I was accelerating. Upon acceleration, I experienced hesitation---none at constant speed.

Note I said "As much". Ive been around to know there are exceptions.

Also note that the trany fluid and filter replacement was because of the op's clunks when shifting.

[scottd9]

I have a 2002 SC1. We recently started experiencing clunking/jerking as the car was moving up & down through the gears while driving. We brought our car into a transmission shop and it was discovered that it was one of the Pressure Control Soleinoids. They replaced it and everything has been great since.

[notmycity]

Appreciate all of the info. I don't have time or the space to do my own work anymore, but I'll share this with my techs.

Good news is the car is under drive train warranty, the bad news is I just got the car back and it's unchanged.

They did however replace a thermal sensor, head gasket and upper motor mount. Doubtful they test drove it as I was able to feel the same problem inside 2 minutes.

Thanks again.

[OldNuc]

I see they(your mechanic) listened well. If they can not scan for it they can not fix it.