2000 Express Van Hesitates

[Wills03]

My van has a problem that is slowly getting worse.

First noticed problem 2-3 summers ago on really hot days would hesitate 10 sec or so after warm start then run fine. No problem with cold start or after hot days went away. In fact I would forget all about in cooler weather.

Now hesitation occurs even after cold start and when rolling into the throttle at the base of a hill. Iam also hearing backfiring in the intake.

Engine light was on once but for only one 5 mile trip then off.

I scanned for codes at found none.

Any ideas.

Thanks,
Wills

 

[Bob_VT]

Re: 2000 Express Van Hesitates

Doesn't that have a mass air sensor? Napa sells a spray cleaner for mass air sensor's and I will give testimony it works fine.

Normally hesitation in newer cars/trucks is from a dirty mass air sensor...... it may not ne dirty enough to be throwing CEL on or codes but just enough to cause problems.

 

[DECK SWABBER 58]

Re: 2000 Express Van Hesitates

Doesn't that have a mass air sensor? Napa sells a spray cleaner for mass air sensor's and I will give testimony it works fine.

Normally hesitation in newer cars/trucks is from a dirty mass air sensor...... it may not ne dirty enough to be throwing CEL on or codes but just enough to cause problems.

+1

Also clean the throttle body while your their.

 

[Wills03]

Re: 2000 Express Van Hesitates

Yes it has a MAS.

I will try the NAPA product.

Wills

 

[Bob_VT]

Re: 2000 Express Van Hesitates

Before you do it .....here is a quickie test

When the engine is running at an idle (while in park) ......press the accelerator pedal as to slightly rev up the engine...... is there any hesitation? That is a good indicator.

 

[Wills03]

Re: 2000 Express Van Hesitates

Yes it will fail that test now.

But two years ago only on a warm restart on a 85* + day.

I take it these MAS are temp sensitive.

Thanks for your help Bob. I have found your posts very informative on many topics thru the years. Wish I could contribute more but I type with two fingers.

Wills

 

[JBow]

Re: 2000 Express Van Hesitates

My van has a problem that is slowly getting worse.

First noticed problem 2-3 summers ago on really hot days would hesitate 10 sec or so after warm start then run fine. No problem with cold start or after hot days went away. In fact I would forget all about in cooler weather.

Now hesitation occurs even after cold start and when rolling into the throttle at the base of a hill. Iam also hearing backfiring in the intake.

Engine light was on once but for only one 5 mile trip then off.

I scanned for codes at found none.

Any ideas.

Thanks,
Wills

Just disconnect the mass air sensor and drive it and see if its better. The pcm will substitute a value that it will run off of. It will set a mass air code and turn on the CEL. If that dosent get you anywhere I would be testing fuel pressure next. Let us know how this turns out.
Jack..

 

[Wills03]

Re: 2000 Express Van Hesitates

Update,

Unplugged the MAS and it ran like a champ for a week.

Then I removed the MAS and cleaned it with the NAPA product and reconnected.

Apears to be running excellent.

Thanks for everyones help.

Wills

 

[roscoe]

Re: 2000 Express Van Hesitates

Really good to hear.

I have a similar issue.
2002 Trailblazer.
Started back in June, seems to be temp and possible high humidity sensitive.
Was so bad on some days that it would kill the engine either when trying to accel or easing up to stop in the first mile or two. Some days it was a problem for up to 7 miles.

The first symptom was trying to accel very slowly from 35 mph. Felt like no timing advance, or a couple plugs weren't firing - then would eventually kick in.


Had it in to the Chevy dealer twice for other maintenance, they could not duplicate scenario or find the cause.

They hosed the engine, replaced fuel filter, checked pressure, checked elec connections.

Only had one code, for a sensor, which they believe was an old unrelated code. CEL never came on.

Now we have cooler weather and it has been fine for 3 weeks.

But, the 02 Trailblazers have the older style "Speed Density" type engine control system.
Maybe that is still where we should be looking.

Thanks for getting back to us and letting us know your results.