93 Camry V6 Bucking

[cg22@tampabay.rr.com]

First I want to say thanks to all who post and reply. It's a pleasure to see others helping others. Especially as prices soar in this uncertain economy.

I am having a bucking issue after about 30 minutes of driving. It does not do it all the time. At first I thought is was the tranny (may still be). It seems to do it between 1900-2500 rpm (mostly between 40-50mph). The Camry only bucks occasionally. It's like there's major power loss for a split second. It did it about 5-6 times after about an hour worth of city driving. Engine power and shifting is great otherwise.

I know there can be many causes (fuel, ignition, exhaust, vacuum, emissions). I am sure I am not the 1st to experience this and hope to find a quick cure from someone who had this problem. Maybe just a simple TPS or timing adjustment? Any ideas guys?

Car has 200k miles, 39k on top engine rebuild, 16k on tranny rebuild. Car was very well maintained (i.e. regular synthetic oil changes (20w50), tranny pressure flushes every 30K, tuneups, etc.) No vac leaks, new Denso plugs, recent throttle body cleaning.

[xtremeskier97]

Im just starting to experience the same exact thing on the LE in my sig.

[cykaaro]

what's the fuel level when this happens? and does it seem to happen upon acceleration?

[samarai912]

have you checked for any codes? probably your best bet.

[Knailgun]

distributor possibly???? maybe the plug wires have given up the ghost

[new echo owner]

Did this happen after you put the plugs in? Have you ever had the plug wires, cap and rotor replace?

N.E.O.

[cg22@tampabay.rr.com]

Fuel level is 3/4-full. I have cleaned and regapped the plugs (yes NEO, it did happen prior to plug cleaning). I have not changed the distributor cap or rotor or wires. The bucking happens on very light acceleration, especially when going 40-50mph. It did occur 1-2 times at 30mph. Seems to happen only in the higher gears (3&4). The auto tranny shifts like a dream. It almost seems like tranny is hunting for gear (3-4), kind of like it don't know where to go for 1-2 seconds. Still not sure if it's tranny or engine.

I seafoamed the car today, 1/3 can in brake booster vac line, let it site for 10 min. Put rest of can into the fuel tank. Drove car 12 miles around city, bucking only occurred 1-2 times. I need to drive the car some more. Seems to be a little better.

I will check for codes tomorrow, good idea. No CEL presently.

[new echo owner]

Are the cap, rotor and wires original? The year is on the wires if you are not sure. A couple of the common problems on those engine are the rotor burnt arcing through to ground or the ends of the plug wires coming off; the rotor will cause hard start or stalling or engine miss, the wire will cause intermittent engine miss.

N.E.O.

[cg22@tampabay.rr.com]

Guys, switched out the rotor as NEO said, no change. Plus wires look brand new or not very old. Failed to mention that the motor has 40K on a top engine rebuild. Also has a whining coming from under timing cover. I assume that there is a bad tensioner, idler pulley, timing belt or water pump. Do any of your Toys make a whining noise from the timing cover? Maybe this is normal for Camrys? Found an oil leak (oil adapter o-ring) and will replace tomorrow.

Had weird experience while engine was 3/4 warmed up (outside temp was 75). Was driving at 50mph, let foot off the gas, then car accelerated to 65 all by itself. It was like the cruise control was on but it was not. It only did this once and stopped when I hit the gas pedal again. Bucking is better but still there. Still not sure if its play in the drivetrain or engine problem. I plan to pull the codes tomorrow too (if any) and will post them.

Skier97, did you start to trouble-shoot your car yet? Did you find anything?

[cg22@tampabay.rr.com]

I purchased new timing belt, 2 idler pulleys, tensioner, and water pump today and plan to fix that whining/moaning noise under timing cover. Never did a timing belt before but did read haynes manual throughly. Any tips on changing or hunting down whats causing the whine/moan? 40K miles since rebuild, seems like belt should still be good. Maybe needs adjustment?

[new echo owner]

Did you replace the cap too?

N.E.O.

[xtremeskier97]

Originally Posted by cg22@tampabay.rr.com

Had weird experience while engine was 3/4 warmed up (outside temp was 75). Was driving at 50mph, let foot off the gas, then car accelerated to 65 all by itself. It was like the cruise control was on but it was not. It only did this once and stopped when I hit the gas pedal again. Bucking is better but still there. Still not sure if its play in the drivetrain or engine problem. I plan to pull the codes tomorrow too (if any) and will post them.

Skier97, did you start to trouble-shoot your car yet? Did you find anything?

I have the same thing happen on my 93 V6. I can be stopped in gear and let off the brake and hit the gas for a split second and let off, and then it lurches forward again after I have already let off the gas. It's like the throttle opens itself again after I let off of it.

Anyone know what could cause this?

And no, I havent had time to mess with the wife's car. I work 14 hours a day and the wife currently has a broken ankle, so Im doing all the stuff I normally do, along with what all she normally does for me and the kids. It's VERY tiring!

I'll definitely post up if I do find out what's going on with it.

[new echo owner]

Originally Posted by xtremeskier97

I have the same thing happen on my 93 V6. I can be stopped in gear and let off the brake and hit the gas for a split second and let off, and then it lurches forward again after I have already let off the gas. It's like the throttle opens itself again after I let off of it.

Anyone know what could cause this?

And no, I havent had time to mess with the wife's car. I work 14 hours a day and the wife currently has a broken ankle, so Im doing all the stuff I normally do, along with what all she normally does for me and the kids. It's VERY tiring!

I'll definitely post up if I do find out what's going on with it.

Have you check your TPS to make sure that the idle contact is working?

N.E.O.

[new echo owner]

Originally Posted by cg22@tampabay.rr.com

I purchased new timing belt, 2 idler pulleys, tensioner, and water pump today and plan to fix that whining/moaning noise under timing cover. Never did a timing belt before but did read haynes manual throughly. Any tips on changing or hunting down whats causing the whine/moan? 40K miles since rebuild, seems like belt should still be good. Maybe needs adjustment?

Take the top timing cover off and listen to it, just be careful of the timing belt turning. Just about everything in there would cause a whining/moaning noise, even the t/belt itself. It has a hydraulic tensioner, doesn't need adjusting.

N.E.O.

[cg22@tampabay.rr.com]

NEO, no new dist caps available in my area, will order one online. I remove timing cover and listened to components around under the cover. Sounds like bad water pump. I grabbed the pump and there is a lot of side play in the bearing. I am almost certain that this is my whining problem. The hose-ear trick works nicely. I plan to cheat and not totally remove the timing belt, just remove the tensioner and then slide the pump out. Hope this works. I marked everything just in case. Also changed the oil-adapter o-ring today, not too bad of a job, just dirty (cleaned all with degreaser prior) this made it much easier. 4 12mm nuts, $10 o-ring and 1 hour time. These o-rings really leak a lot when they start. I had oil and sludge everywhere. I plan to finish the water pump on Sat and then check for engine codes. Then attack the "bucking/play in drivetrain problem".