Harsh Shift P0107

2000 Astro LS AWD 137K

After some P/M work, I got a P0107 code and shortly after that I started to get a harsh shift between 1st and 2nd. While I was cleaning the throttle body, I removed both sensors to clean the buildup: is the sensor aft of the throttle postion sensor the MAP sensor? I was not able to move the plunger on the sensor and it was pretty gummed up, but I felt the cleaning solution might damage it. Am I on the right track here?

Thanks

If you are asking about the device on the throttle body, just rearward of the TPS and on the same (left) side, that would be the Idle Air Control motor (IAC).

http://72.19.213.157/files/CPI-IAC.jpg

You should avoid getting any cleaners into the stepper motor windings if possible. It can be disassembled like any other GM IAC for cleaning and lubrication.

The trouble code you listed indicates a low input at the MAP. This can be from a poor electrical connection, failing MAP, or leakage at the upper plenum. The MAP is directly connected to the upper intake plenum on the right side, immediately to the right of the injector pod connector.

http://72.19.213.157/files/CPFIAssembledPlenumID.jpg

Thank you Mr. Bowtie!

When I had the IAC out, I had no idea it disassembled, let alone moved for all the crud. Next time in, I'll see what I can do there. I may have bumped the MAP Sensor connection, last time in, but I wasn't in that area. I'll check that one. Would a suddenly clean throttle body change air pressure enough for the code?

I have to check the radiator fluid quite a bit in the hot weather due to the intake manifold leak (how can GM get away with that one?) until I can change the gasket - it stalled for the first time on me today (idling at a light) and it was the first time I've seen the temp gauge over the mid point. Took a quart and a half to get the fluid to the hot line and a while to cool down.

Any pointers on cleaning the intake manifold - since the throttle body was caked, I imagine it's pretty thick in there, too. By the 2nd picture, can the intake manifold be removed at that level of assembly, or will I need all the clearance I can get in an Astro?

Thanks again for the illustrations. You could put a better manual together than Chilton or Hayes combined with those graphics.

harryevan

Once you get it out, you can clean the upper intake/plenum with hot soapy water. Pristine clean is not necessary. Just get the majority of the crud off and make sure the gasket sealing surfaces are clean.

The upper plenum can be removed, then the lower intake. You won't have to raise, lower, or otherwise move the engine in the vehicle. The AC compressor gets a little interesting, but that's about all.

Not all of the 262 V6 engines have the intake sealing problem. The percentage is fairly low, but since so many were made, the numbers are pretty high. 1% of 5 million engines is still 50,000 failures.