Hard vibration

toyota
camry

#1

My 1994 Camry has as a hard vibration when at or below 1000rpms. Had five shops do one thing or another. Replaced all motor mounts, two different shops did a compression checks and all was fine. The last shop first tried a cleaning spray on the throttlebody and then removed it and spent one hour on the bench to manually tear it down and clean it. Installed and the vibration continues. Overall, I have spent over $1,100 trying to get this problem fixed. Any ideas? Thanks.


#2

Does it do this at idle, or only when you’re moving? If it does it when you’re stopped, does that include when it’s in neutral/park?


#3

Since you mention the 1000 rpms I’ll assume that you have a tachometer. So when you are just sitting at idle, where are the rpms? Does it remain steady or perhaps wander around or surge?

The idea that compression is “fine” is very ambiguous. There are many interpretations. On one or both of the shop invoices the actual numbers (in psi) should have been written down. Find those numbers and post them.

Presumably all of the other basics have been checked or otherwise dealt with? - spark plugs and wires, fuel pressure check, fuel filter? Was the idle air control valve (IAC) also cleaned when the throttle body was cleaned?

Have someone temporarily remove the vacuum line from the EGR valve. The vacuum line has to be checked for leaks, and then cap the valve and plug the line to see if anything changes. This is temporary. If it helps then the EGR problem needs to be worked out.


#4

In addition to what’s already been mentioned, think valves. If the valves are not opening and closing evenly due to a worn valvetrain or gummed up hydraulic lifters/tappets, the compression, the fuel metering, and the ignition system could all be perfect and the engine still won’t operate smoothly. This’ll be obvious with a vacuum gage.

How many miles on this baby anyway?


#5

I’m assuming by “hard vibration” and what all has been done to fix it, the shops think the engine is idling poorly. Idle speed is probably around 800 rpm on that car. I have a 90’s Corolla, and if I had that problem first things I’d do is what you’ve already done, mounts, and clean the throttle body. If that didn’t fix it … hmmm … next up would probably be …

  • Bring all recommended engine maintenance (per owner’s manual) up to date, including new air filter, dist cap/rotor/spark plug wires (if applicable) and checking valve timing, valve clearances, ignition timing and idle rpms.
  • Read the ECM’s diagnostic trouble codes.
  • Check PCV
  • Check EGR
  • Check IAC
  • Check throttle position sensor
  • General vacuum leak check, esp brake booster and power steering pump
  • Exhaust leaks
  • If still a problem, I’d replace the O2 sensor if original to car