Stumbles but no error code?????

[sampsongrsk]

Hey everyone, i know the place to go for help with my camry and here I am....


98 camry 4cylinder, 131k...

Recently my car has been bugging me, a day after replacing a door lock actuator (insanely hard with no directions) my car has begun to stumble, almost like it is missing a cylinder. It happens more often when in drive: when stationary in drive it idles at 600rpm but stumbles to 400 or so when it dips. The bulb on the check engine light is not burned out, and my mileage is still good (24-25mpg on city streets) so I am completely lost! I was thinking of replacing my pcv, vcv and egr valves but the egr is like $190! I did a visual inspection of the vacuum hoses cant see anything wrong, replaced the plugs (copper, ya i know platinum lasts longer). Dunno if the timing belt was ever replaced, but on visual inspection it does not have any cracks or fraying. I am completely lost!!!! Any, and i mean Any help would be greatly appreciated! The car is in great condition and has been babied for the longest time.

thought the cat would look good here...

[DFBonnett]

Sounds like a random misfire. How old are the plug wires? You mentioned new plugs. Did you use NGK or Denso? Camrys often have difficulties with aftermarket brands.

[Kep]

As you have discovered, just throwing parts at a car can be expensive. However, you can inspect the EGR to see if it is inoperative. If you disconnect the actuator vacuum line and suck on it and let it go you can usually hear the valve inside operating. If the car is running and you remove the vacuum line (you'll hear the vacuum) the engine should change (if you don't hear vacuum then it may not be "on" or there may be a different problem).

However, this would be a perfect time for "Kep's Trilogy." Clean the EGR system, the throttle body and the IAC valve.

In fact, Marc780 just did a great write up on throttle body cleaning at:
How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures

Kep

[gonesurfing]

The 4cy plug wires are PITA to get out. It is possible that one of them was damaged when the plugs were replaced. I had a similar problem on a Cherokee where after replacing the plugs, one later started arcing to the engine block causing a dead cylinder. Pull the plug wires and look for carbon on the boot of each plug wire.

[Mike Gerber]

If it is actually a missfire, it will eventually light the check engine light (also called the MIL lamp) and there will be a code stored. Your car is OBD2 compliant. The code will either be P0300, P0301, P0302, P0303 or P0304. Having the code read will tell you whether it's one cylinder or a random missfire on all cylinders. That will tell you where to look for the problem.

Mike

[sampsongrsk]

for the life of me i cant figure out what is wrong, checked all hoses, most valves and nothing... i do have an idea, im going to take some videos and pictures and post them, i think the valve that controls idle speed might be bad, hopefully my camera can take good pics...

[sampsongrsk]

http://www.youtube.com/watch?v=DTIxiv3gDbQ


that is a short video of what its doing, if you can think of anything else for me to try please let me know... I cleaned the throttle body extensively, no real difference, the hoses are not leaking as far as i know... I am not too good with vacuum systems so any pointers would be appreciated!

[sampsongrsk]

i know it doesnt look bad when it stumbles via video, happened alot more often tonight when i went to a 24 hour store, kinda real bad.... anyone have any thoughts????

i dont think it is the idler valve...

kep, do you know where the egr vacuum line is that you are speaking about???

[sampsongrsk]

So i took it to a shop today, they checked a few things...

said it may be a bad valve, the compression was about 16psi on cylinder 4, not good....

I am kinda worried because there was no engine light before he worked on it and the problem was intermittent, then afterwards the light is either on or flashing, and the problem is constant throughout the gears and acceleration.

Anyone think that he may have intentionally done anything, the only thing I saw him do was check compression by replacing the sparkplug with some sort of gauge....

Any second opinions???

[Kep]

Get the code read at an auto parts store for free. Gonesurfings point is well taken. It is ridiculously easy to break a spark plug wire and the mechanic may have done so. If the code is one of the ones that Mike mentioned it may well be that you now have a misfire from a broken wire in addition to your previous problem. If you have a lifetime warranty on your plug wires it would be easy to replace them and see if the problem changes back to "normal". Otherwise, you can check their resistance (I believe that 20,000 ohms or less is still the range you want to be in) but each time that you pull the wires you take the chance of doing damage.

I don't know if low compression would throw a code or not. However, I can envision an intermittently seating valve giving you a stumble like you described. You may want to seek a second opinion, especially if you suspect the first one intentionally or unintentionally damaged your car further.

Kep

[sampsongrsk]

PROBLEM SOLVED..


very much so..

the first guy definitely was trying to sucker me, compression is 150ish clear across the board.

The Honest Mechanic told me that he could hear sounds from the timing belt area and thinks i should replace, the plugs i had in were wrong and that the plug wires were incorrect and most likely needed to be replaced...

going to replace timing belt, kept the copper plugs because they have less resistance than platinum and put in recommended wires...

WORKS LIKE NEW!!!

all of this due to incorrect (4mm???) wires being on car, suprised it didnt start going wrong sooner.

This is the second time that spark plug wires won a drawn out punch in the face match with me (girlfriends 2002 SL1 Saturn).. My advice to anyone: when in doubt, replace plug wires & check to make sure there is a spark!

Thanks for all the help guys!