I have a 98 Millenia s, bucks when given 1/2 throttle or more once engine has warmed to normal operating temp (about 20 - 30 min), happens faster with load on engine such as a/c or defroster. Dealer has gone thru vac lines and replaced solenoid pack but problem still present. Also have replaced plugs (NGK's), coils (all 6), TPS, MAF, Speed Sensor, and fuel pressure regulator to no avail. Thought it might be precats,so Ipulled all o2's and drove car to see if problem still exists and it did. Any help or ideas would be greatly appreciated. Again I am not getting any codes at all.

 

for some reason, i cannot answer your pm. what is your email?

 

Probably something to do with your tcs. I heard other callers complain of this problem, especially when the car is under a load.

 

I had the same issue with my 98 Millenia. The check engine light would come on too. And failed the smog test mesirably.

Check the air intake hose for cracks/holes. You will not see it (in my case, them) unless you bend the hose hard or pull the hose out. After I replaced the hose the problems went away and it passed on the second smog test.

The mechanic at the dealer (where I bought the hose) told me that the holes on the hose would certainly cause these problems.

Hope this helps.

 

The emissions can be difficult. However a cousin of mine used an additive he read about in his miata and it passed with flying colors after failing. I think it was at www.SmogSecret.com He swears by it. Good luck.

 

I know this sounds odd since it is not really 'engine' related but my 94 did a really weird bucking thing too at lower speeds. Also if I turned the wheel hard to the right it clicked....turned out to be an axle... replaced that and problem solved!! Like I said I know it sounds strange but the axle caused it to buck a little at lower speeds!