Hesitation At Motorway Speed

[DGB]

1996. 25th anniversary Celica,hatchback automatic 154,000 . After a number of years of essentially trouble-free driving, with careful maintenance and a good mechanic, we now have a fairly frequent hesitation when doing anything from 50-70 on the open road. Our mechanic says to drive it until it becomes more serious since he has tried everything that he can think of. That is okay for us, but we do house exchanges and have to have a comfortable ride for our exchangers.

Any suggestions wlll be followed. Derek

[buklau111]

Sorry but you did not mention the problem and what makes you hesitate from driving on the motorway.

[DGB]

Perhaps you are joking - in which case, yes my wording was careless. It is, of course, a momentary bump in the smooth running of the motor, but thanks for the smile to start the morning. Now can you offer any ideas on the cause?

[gazza1286]

Is it hesitant when you maintain a steady speed or during acceleration? When cold or only when up to temperature? Fuel filter changed recently? These sometime get neglected and for that vintage should be at every third service or 27k miles.

[DGB]

It only happens when the car is actually up to speed and going along with only small adjustments. The engine would be fully warmed up by this time.

The fuel filter is a good suggestion, and I will check my records when I get home - but probably change it anyway. Thank you for the suggestion.

By the way, the car has spent all of its life in South Florida if this is of relevance.

[Cyker]

Is it like a 'cough' or just the engine reacts sluggishly to throttle changes once you're going at speed?

Need to narrow it down a bit more; Might be fuel related (not getting quite enough fuel when running at speed; fuel pump or filter?) or electrical (sparks a bit dirty? HT leads worn?)

[gazza1286]

Would running it on Super Unleaded be worth a go? That or putting a can of injector cleaner in the tank next time you fill up.

[DGB]

Thank you both. The acceleration has no problems, and "cough" (or a few "hiccups") is a good description of the problem. It may do it a few times, or may recur through much of a trip when at that highway speed.

I will try any and all suggestions, but one at a time since I have seen other people's posts who have cured a problem with multiple changes and never did know which was the real cause. I learned that in other aspects of life !!!