Girlfriends 97 Camry Having a Few Problems

[NightRider97]

To start with I have a vast array of mechanical experience, most of which is with restoring classic cars, but lately have been tooling on modern cars as well. My girlfriends Camry started having a stuttering, stalling, problem last week and after her shop told her they wanted $750 to do several simple maintenance duties I told her I would do everything I could do before she took it in. I completed the entire list of service duties they had outlined on their invoice and the car is showing the same problem, plus now we are noticing its not getting the fuel mileage it used to.
Here's the list of what I did.
Change plugs (went with the OEM NGK Laser Platinums)
Plug Wires
Valve cover gasket and plug tube gaskets (because of oil in one plug tube)
Fuel Filter
Clean throttle body

Now I know sometimes throttle body cleaners can damage the O2 sensor, but it didn't throw any codes for such a problem.
I have a logging program that I can plug into the OBDII port and record the data the ECU is receiving, when doing this I noticed the timing is irratic and extreme at times, as well as the TPS is showing 10% at idle and that should be 0%. I just dont know where to start. Should I reset the TPS? I'd imagine there is some sort of idle position switch built into the TPS and if its not showing it should be idling that would cause a problem. Could someone tell me which terminals I need to reference to set the TPS?

EDIT: Its a 97 with the 4cyl engine, not the 6.

[fenixus]

check the EGR system. most likely there is a vacuum leak or EGR valve is very dirty and getting stuck in some position. ECM might not pick this up (error detection for this system sucks on this model of car), had this problem before, ended up rebuilding the whole EGR sub-system and now MPG returned normal.

there is a DIY on removal and cleaning the EGR valve in FAQ section. troubleshooting vacuum leaks is a PITA on the other hand.

5s-fe's normal TPS at idle can reach up to 16% and is normal (nowhere near zero). BTDC is usually set to 10, so expect ignition advance timing anywhere between 5-11 at idle.

how are your fuel trims an o2 sensors wave forms look alike ?

did you spray some TB cleaner into the IAC holes in TB as well ? mine was dirty as hell (IAC inlet hole), was looking like there was dirt in it.

for more detailed troubleshooting refer to factory service manuals here:
http://www.camrystuff.com/index.php?page=Gen4_Manuals

especially pay attention to manuals: Diagnostics, SFI, Emissions and TSBs.

[LynchburgCSI]

I thought the TPS was supposed to show 10% at idle. Hmmm. Maybe someone else can chime in there.

Have you ran a cleaner like sea foam into the brake booster vacuum line? Fuel injectors doing okay? What's the mileage? 4cyl or 6?

Andddd, not a huge deal, but OEM brand aprk plugs are Denso/NipponDenso. NGKs work fine too. Also, what brand are the plug wires? OEM ones tend to be the best along with NGK ones. NEVER use Bosch stuff on a Toyota. Big rule around here. It causes all kinds of issues.

[fenixus]

Originally Posted by LynchburgCSI

I thought the TPS was supposed to show 10% at idle. Hmmm. Maybe someone else can chime in there.

6-16% is norm on TPS at idle for 5s-fe per engine normal operating sheet in Diagnostics manuals. 1mz-fe has a different normal range (7-11% or so)

[LynchburgCSI]

Originally Posted by fenixus

6-16% is norm on TPS at idle for 5s-fe per engine normal operating sheet in Diagnostics manuals. 1mz-fe has a different normal range (7-11% or so)

Thanks. All i know is that my old 5S showed 16%.

[fenixus]

Originally Posted by LynchburgCSI

Thanks. All i know is that my old 5S showed 16%.

no probs. to put things easier to check. i can say that those numbers are meaningless, but what matters is that either of port P and port R on TB MUST show zero vacuum at idle (easy to check with a handy mityvac pump), otherwise it means the throttle plate is not fully closed at idle (even if TPS shows e.g. 14% it can happen) and then the throttle screw needs to be adjusted down.
had this problem after some home repairs long time ago, shortly after purchase, was trying to cover up bad idle when i had a fouled spark plug (wasn't aware of that)

[NightRider97]

Ok, well I guess I deal with sports cars too much, lol. Every modern car I've worked on aside from this one required the TPS to be set at 0% at idle or there would be all sorts of issues. Good to know, better to know that than chase a problem that doesnt exist.
I cleaned everything I could in that TB, including the IAC port in the base of the throttle body. Unless I'm missing something.
The possible "problems" with the EGR system baffles me, because I found 2 hoses that the previous mechanic had left unhooked, I put them back on, as well as replaced one cracked one. It never showed poor mileage until after I worked on it.
I have a few logs of the car running, idling and cruising if anyone is interested in seeing them.
What I noticed was weird about the timing was that it would read 5-7* at idle, and 16-21* cruising at times, then other times it would be 41-52* cruising.
Front O2 sensor was cycling between. .1v and 4v IIRC.

[fenixus]

Originally Posted by NightRider97

Ok, well I guess I deal with sports cars too much, lol. Every modern car I've worked on aside from this one required the TPS to be set at 0% at idle or there would be all sorts of issues. Good to know, better to know that than chase a problem that doesnt exist.
I cleaned everything I could in that TB, including the IAC port in the base of the throttle body. Unless I'm missing something.
The possible "problems" with the EGR system baffles me, because I found 2 hoses that the previous mechanic had left unhooked, I put them back on, as well as replaced one cracked one. It never showed poor mileage until after I worked on it.
I have a few logs of the car running, idling and cruising if anyone is interested in seeing them.
What I noticed was weird about the timing was that it would read 5-7* at idle, and 16-21* cruising at times, then other times it would be 41-52* cruising.
Front O2 sensor was cycling between. .1v and 4v IIRC.

if any vacuum hoses were unhooked before then car was loosing vacuum. since you hooked them on and replaced a cracked hose then you closed the loop and possibly you may be observing a stuck EGR valve problem (not sure which hoses we talking about, but most of them around engine are EGR and PCV related).

if you have a narrow band (thimble type) o2 sensor pre-catalyst (per federal emissions specs) then range of 0.1V-0.4V is bad. it should be rather rapidly alternating between below 0.4V and above 0.6V.

if your car is california specs based then the upstream (pre-cat) sensor is an AFR (more expensive) and usually it shows only a constant voltage level (e.g. 2.7V, 3.3V or 3.8V, etc. no alternating) as it is much more precise.

if you sealed all vacuum leaks (would be good to see the fuel trims and o2 sensor waveforms to make sure) then I would say that your engine is running LEAN or at least the sensor reports it like that based on what you described. may be a bad o2 sensor though.

try using a 24oz bottle of techron in fuel tank to see if idle improves, if yes then problem might be fuel system related (.e.g. clogged/dirty fuel injectors).

how is your Engine Coolant Temperature sensor reporting ? correct temps ? if this one goes bad it brings havoc.

[73sport]

^ +1 nice work Fenixus!!

Something I would do to isolate the EGR issue is to determine how the EGR valve is performing right now. The tub in the back going into the EGR should be cool until you lightly rev the engine and hold it there (correct me if I'm wrong, as I think the ECM wants vehicle speed too) but the point is, in the driveway at idle is should be cool at idle. If you connect a vacuum source to it and apply 5 - 7inhg it should make you engine stumble and maybe even die. The diaphram should hold a vacuum and the tube in the back should warm as exhaust gases pass through it (while vacuum is applied).

This gives you an idea that if the proper signal WAS applied the mechanical connection is present and working. It does not rule out a leaking EGR valve.

As Fen pointed out, follow the EGR trouble shooting guide under the EGR section.
Also, the timing is going to be all over the map, I think that's pretty typical.

How does the timing look? Do you have means to check this?

[NightRider97]

Well it acted like it was running great for several days, gas mileage seemed pretty normal, and now it has thrown 2 IDC's.
P0441 and P0302
The first one is for the evaporative emission controll system incorrect, purge flow.
The second is cylinder 2 misfire detected.

So yea, now that I've replaced the spark plugs and wires with new ones, NOW it shows a IDC for a cylinder misfire.
I'm not sure what the deal is with the EVAP system, maybe that was one of the hoses that was left unhooked? Maybe for this reason?