Shake at Idle

[Sethro]

Recently when my '97 SOHC is at idle, it will every so often quiver, or shutter very slightly. It seems to be getting worse and doing quite often. I don't know if it has anything to do with it, but it start shortly after I put my KKM on. Suggestions...

 

[Alec]

When you installed your KKM, did you disconnect the battery and let the computer memory bleed out? Did you then let the truck idle for 10-15 minutes with no accessories on? If you didn't I'd say it's the computer spazzing out a bit.

Do the RPM's change when the truck does this? Also, does this happen with both the A/C on and off? And does it matter if the engine is warm or cold?

 

[Sethro]

I disconnected the battery for about 5 min, I didn't let it idle for the 10-15 minutes, I'll try that this weekend, I haven't used the air yet, RPM's don't budge, and I don't think that engine temp has any effect on it...

 

[Alec]

Cool, thanks for the answers. I have a feeling it might be the computer. If it isn't, it's probably some sort of minor SOHC problem and I don't know much about the SOHC engine. Maybe someone else can help.

Anyway, disconnect your negative battery cable for 15+ minutes. The longer the better, to let the computer's memory fully bleed out. Then, reconnect it and let the truck idle in park for 10-15 minutes with NO accessories on. Then drive the truck around town for a bit, and drive it a little hard. Try to get a few good highway on-ramps in there also. This will reset your computer and let it fully adjust to the new filter. But if your problem persists after that, hopefully someone else will chime in to help.

 

[Ricardo Miramontes]

Shudder at Idle

I recently posted a similar question about my 1998 XLT SOHC and was told that it had something to do with how the SOHC engine resonates. Mine has gone as much as having the exhaust vibrate and make a somewhat irritating noise. Mountaineerman helped me out with this problem by telling me that there was a TSB out there for this problem. Do a search for my name or that of Mountaineerman's and I'm sure you'll find the answer. I believe the fix is buying a Y bracket that bolts to the transmission bellhousing and a U bolt that braces the exhaust. It is better explained in Mountaineer man's response.

Hope this helps.

 

[mountaineerman]

Ricardo -
Did you ever install the bracket? That was the best $80 I ever spent. I had forgotten all about this past problem until I read this post.

 

[Ricardo Miramontes]

Moutaineerman, You're probably going to think I must be one of the most inexperienced persons out there, which I guess when it comes to major car repair it may be a true statement. No I have not installed it. I still have the bracket, and the U-bolt but have not been able to figure exactly where it goes. And I didn't want to bother you any further. I'll keep trying though.