I did some basic engine maintenance and after I finished I started the engine and it made this horrible rattling noise. The engine struggled to stay running, almost died then recovered and smoothed out. I drove it around the block and it was smooth as silk and ran better than ever. My assumption is that I sprayed too much throttle body cleaner down the intake tract and despite sitting for an hour before startup the puddle of fluid must have caused the engine to choke. Any ideas? Ohh I almost forgot, my MAF was extremely dirty! There appeared to be a chunk of soot covering the 2 wires such that I couldn't even tell there were wires in there. The PCV was dirty but operating just fine despite 128k miles.
+1 on your assumption, sounds like it was just consuming the cleaner. One time, the first time I did a valve clearance adjustment, on an Accord, I managed to mix up the intake and exhaust sides when setting the gaps (they have different values: exhaust clearance being greater). It ran really rough when I started it up, and didn't improve. Well, until I set things right.
I agree with F8L's assumption. BTW the Toyota TSB relating to Classic throttle body cleaning does not recommend spraying cleaner into the throttle body. Rather, spray the cleaner on a clean cloth or paper towel and use that to scrub the body interior and throttle plate. The reason for using minimal cleaner is to prevent dirt from being carried into the throttle motor via fluid runoff along the throttle plate shaft. A secondary reason would be to avoid the rough start that F8L experienced. Hopefully F8L will experience improved mpg with the cleaned MAF sensor.
Thanks Mendel and Patrick. Next time I clean the TB I'll do it the way you suggested. That rough start up makes me cringe so I'll do anything to avoid causing it again. I accessed the PCV by removing the relay box, air box, and wiring harness plate as well as one of the spark plug wires. I didn't feel like taking the cowl and windshield wipers apart. The most time consuming part was trying to break the PCV lose. It was tight!
F8L I hope you did not drop something into the throttle body, but most likely pr-ignition from the cleaner solution? Hal
Thankfully the throttle blade stays shut unless you open it so I always double check the opening as well as shine a light down in through the TB with the blade open just to be sure the area is free of dropped items like screws. I used to port and polish TBs for our Camaro/Corvette club so I'm usually hyper careful about stuff falling into an open engine. I used to remove TBs to clean them or the engine would be running so I didn't think of fluid buildup. Bad juju. lol
