Hesitation on acceleration - gears slipping?

[riproaringca]

Hey all.

Here's a question for anyone with prior knowledge of something I'm experiencing on my '99 2.0 (automatic w O/D) ZX2:

When pulling away from a standstill the car seems to hesitate briefly, almost as if it's choking, then pulls away. I find it usually happens when the car's warm, and happens less in the winter when the outside temp is cold. The sensation it gives is what I'd expect if the transmission was slipping out of and then back into gear. There is a small 'jerking'.

With this description can anyone share some wisdom on what I might be experiencing?

Many thanks!

[Davescort97]

I just know you've done this, but have you checked the fluid level in the transmission? How many miles (kilometers) are on it? The PCV valve may be worn or an engine mount or tranny mount may be loose. The CV joints could be worn. Is it making a clicking noise upon turns?Does it do it in all gears? Does it do it according to engine speed or at any speed but just when it shifts gears? When you first put it into Drive does the tranny slip before it goes into gear? How's your fuel mileage? Hasn't it gone down recently? Is the speedometer OK? Have you good fuel pressure at the rail? Has the timing belt been changed recently?

[riproaringca]

Here's an update on the performance of my ZX2 since posting the original thread:

• replaced front engine mount which was worn/corroded
• replaced muffler and exhaust pipes from the Y pipe back (the catalytic converter was fine, thank goodness) and this corrected an improper level of backpressure
• replaced one tie-rod end

Car is running much better. Still some hesitation when either first pulling out of the drive in the morning, car still cold or the odd time when fully warmed-up in stop-and-go traffic. But it is much improved and not nearly as worrisome as before.

I plan to:

• replace transmission fluid and screen
• inspect CV joints
• change timing belt

I can confirm that:

• fuel pressure is good and filter is clean
• PCV valve is clean and operational
• there is not a clicking noise when turning
• gears shift fine through acceleration and deceleration speeds
• speedometer works fine
• fuel mileage is acceptable and hasn't dropped noticeably (approx 600km/370mi to a full tank)

Stay tuned...

[danielsatur]

Try cleaning the MAF/IACT sensors & connectors with CRC MAF sensor cleaner.

[Davescort97]

I'm thinking it could be something as simple as dirty fuel injectors. Could you run a bottle of fuel injector cleaner into the tank?
3

[danielsatur]

How about an ''Out of car injector service'', a diesel shop will micro bath, blow out, and do a flow test.

Also consider a good throttle body cleaning, because of all the EGR + PVC gunk.

[mchlcordell]

Change out the fuel filter, the most common problem to have.