MAP sensor replaced, still having slight issues, perhaps O2 sensor?

[guccimane]

so my Camry is running rough. I replaced the MAP sensor and the problem improved dramatically, but there's still a slight problem.

the car runs a whole lot better post-MAP sensor replacement, but, for example, the car's RPM gauge still bounces up and down really only when I'm in reverse. I haven't really noticed it at other times, but maybe it would do that when i'm in park and I just don't wait long enough...

also, the engine seems to be a tad bit slower than it used to be when I press the gas to go faster.

for what it's worth, I originally had the "too rich" error codes. back when that was happening the engine would have an extremely difficult time going beyond 2k rpms and would sometimes shut off totally.

my personal thoughts on the matter is that perhaps the contacts to the MAP sensor need to be cleaned or that the vacuum tube is cracked slightly and leaking, but I don't know.

what do y'all think? does the MAP sensor explain the tachometer bouncing up and down during reverse or do you all think that's coincidence?

Thanks a lot! this is the only problem I'm having and I love my Camry, so I'm eager to fix it.

edit: maybe it's normal, but the engine does seem to be pretty hot when I pop the hood, but the instrument cluster temp gauge doesn't ever go beyond halfway on the gauge and that's where it's always been even when the car was running fine, so I suppose that's normal?

[JohnGD]

Go to Autozone, borrow a MityVac on their loaner tool program. Measure the manifold vacuum at idle at the EVAP port on the throttle body or tee it into the MAP hose (a plastic tee and extra vacuum hose needed). What reading do you get?

Plug the MityVac (using the pointed adapter, if it comes with one, or a plastic coupler 3mm, 1/8") in place of the EGR valve. With the engine warm, what readings do you get at idle and at 3000 rpms?

Whats your idle rpm?

I'd consider cleaning the IAC valve by disassembling it (remove the thermostat cover and motor so the rotor can spin freely as you clean).

[guccimane]

Originally Posted by JohnGD

Go to Autozone, borrow a MityVac on their loaner tool program. Measure the manifold vacuum at idle at the EVAP port on the throttle body or tee it into the MAP hose (a plastic tee and extra vacuum hose needed). What reading do you get?

Plug the MityVac (using the pointed adapter, if it comes with one, or a plastic coupler 3mm, 1/8") in place of the EGR valve. With the engine warm, what readings do you get at idle and at 3000 rpms?

Whats your idle rpm?

I'd consider cleaning the IAC valve by disassembling it (remove the thermostat cover and motor so the rotor can spin freely as you clean).

Thanks a lot for the quick response! I'll do what you recommended, I'm putting together a word document of all the stuff I'm reading in other threads and I've added your stuff to it.

TN really is the best.

any other things you or others might suggest checking?

I was reading in another thread that the thin vacuum tube that leads to the MAP sensor sometimes can crack, so, if that is the case, is that tube expensive to replace?

I'm still going to check everything else out, though, but that tube is pretty small and looks prone to cracking so that's on my list of suspects.