Any auto mechanics here? Need help...

Tony G · #1 03-23-2008, 10:32 AM

My wife's 2002 Mazda Protege5 hesitates when accelerating from a stop, like a traffic light or stop sign. It doesn't happen every time, but lately it seems to happen more and more. What happens is when you press on the gas to start going, the car just bogs down for about a second or two and then starts going again. We've tried the fuel cleaner and that doesn't seem to work. I've also replaced the fuel pump filter and air filter and that has had no effect either. Her car has about 88,000 miles on it. Please help!!!

Mike N · #2 03-23-2008, 10:49 AM

Check engine light on?

Tony G · #3 03-23-2008, 10:50 AM

Quote:

Originally Posted by Mike N

Check engine light on?

No sir.

mimaz · #4 03-23-2008, 10:53 AM

Do the RPM's "bog down", or does the engine race a bit as the car tries to get started moving?

HollowBassman · #5 03-23-2008, 10:53 AM

Does it idle a little rougher than normal?

Tony G · #6 03-23-2008, 10:56 AM

Quote:

Originally Posted by mimaz

Do the RPM's "bog down", or does the engine race a bit as the car tries to get started moving?

No, the engine does not race as you said. The RPM's seem to bog down, almost like the car wants to stall. But then after a second or two, it picks up and drives just fine. I really mean a "second or two" as well. It happens right as soon as I press on the gas to accelerate from a stop, bogs down for a moment, then goes on like nothing happened. Also as I said in my first post this doesn't happen every time but seems to be getting more and more frequent.

Mike N · #7 03-23-2008, 10:57 AM

If the car has a mass airflow sensor (maf) I'd try cleaning it with a spray cleaner like gumout or equivalent. If the elements in the maf get dirty it will cause a hesitation like you describe.

One word of warning- never use anything other than a spray cleaner to clean a maf. You don't want to touch the elements with anything like a q-tip or screwdriver etc....., or you will damage the maf.

Tony G · #8 03-23-2008, 10:57 AM

Quote:

Originally Posted by HollowBassman

Does it idle a little rougher than normal?

No, I don't think so.

Tony G · #9 03-23-2008, 10:58 AM

Quote:

Originally Posted by Mike N

If the car has a mass airflow sensor (maf) I'd try cleaning it with a spray cleaner like gumout or equivalent. If the elements in the maf get dirty it will cause a hesitation like you describe.

One word of warning- never use anything other than a spray cleaner to clean a maf. You don't want to touch the elements with anything like a q-tip or screwdriver etc....., or you will damage the maf.

Ok, I'll look into that. Any suggestions for a good spray cleaner for this job? It was also recommended to me on another forum that it might be a dirty or clogged EGR. Any thoughts on this?

mimaz · #10 03-23-2008, 11:01 AM

At 88K miles, I would also be wondering:

When was the last time you put in fresh spark plugs?

Could you have a bad fuel injector(s)?

Neither would necessarily turn on the check engine light right away, but as the situation gets worse, you may get a check engine light as a result of a misfire code.

Mike N · #11 03-23-2008, 11:02 AM

Quote:

Originally Posted by Tony G

Ok, I'll look into that. Any suggestions for a good spray cleaner for this job? It was also recommended to me on another forum that it might be a dirty or clogged EGR. Any thoughts on this?

Any type of spray cleaner is ok. If you find one labeled as "air intake cleaner" or similar that would be ok.

Unplug the vacuum hose from the egr and see if the problem goes away. Haven't seen too many Mazda's suffer from too much egr causing a hesitation, usually the egr ports plug up on them which won't cause any problems other than an illuminated check engine light.

Tony G · #12 03-23-2008, 11:08 AM

Quote:

Originally Posted by mimaz

At 88K miles, I would also be wondering:

When was the last time you put in fresh spark plugs?

Could you have a bad fuel injector(s)?

Neither would necessarily turn on the check engine light right away, but as the situation gets worse, you may get a check engine light as a result of a misfire code.

We bought the car used with about 55k miles on it, and I haven't done a plug change. It is probably overdue for that, as I doubt they would have been changed before that.

HollowBassman · #13 03-23-2008, 11:09 AM

My S-10 had a similar problem, turned out to be a bad spark plug wire.

Tony G · #14 03-23-2008, 11:09 AM

Quote:

Originally Posted by Mike N

Any type of spray cleaner is ok. If you find one labeled as "air intake cleaner" or similar that would be ok.

Unplug the vacuum hose from the egr and see if the problem goes away. Haven't seen too many Mazda's suffer from too much egr causing a hesitation, usually the egr ports plug up on them which won't cause any problems other than an illuminated check engine light.

Is it safe to unplug the vacuum hose and run it like that for a short while? As I said, it doesn't happen every time, so I'm not sure how many stop/starts I'd have to make to get it to repeat the problems I'm having.

MoD_Scotty · #15 03-23-2008, 11:26 AM

Definitely change the spark plugs, and make sure they are gapped correctly (the specs should be listed in the owner's manual).

It almost seems like there is a problem with the TPS (Throttle Position Sensor). It's what tells the engine how far you're pushing the gas pedal.

I've circled the TPS in red. Find a auto parts store that has a good return policy, and try swapping it out.

EDIT:The TPS might also just be aligned incorrectly. There should be a couple screws on it that allow you to adjust what angle it sits at. You could try moving it around first, before you get a new one. Also, try unplugging it completely. If the car runs exactly the same with it unplugged....or BETTER, it is most likely the culprit.

There are a million other things it could be though. Could be a vacuum leak. The way to test for one is to let the car idle, then slowly spray (a small shot at a time) brake parts cleaner around the engine. If the engine ever revs up on it's own, you know it's sucking in the brake parts cleaner, and therefor has a vacuum leak.

mimaz · #16 03-23-2008, 11:30 AM

Quote:

Originally Posted by MoD_Scotty

Definitely change the spark plugs, and make sure they are gapped correctly (the specs should be listed in the owner's manual).

It almost seems like there is a problem with the TPS (Throttle Position Sensor). It's what tells the engine how far you're pushing the gas pedal.

I've circled the TPS in red. Find a auto parts store that has a good return policy, and try swapping it out.

Good suggestion, but keep in mind that the TPS may be considered an electrical part, which is often NOT RETURNABLE at many parts stores. Be sure to check the policy at the store if you're gonna try this out without knowing for sure that it's bad.

MoD_Scotty · #17 03-23-2008, 11:32 AM

Hence the "find a store with a good return policy" part of my post.

mimaz · #18 03-23-2008, 11:49 AM

Quote:

Originally Posted by MoD_Scotty

Hence the "find a store with a good return policy" part of my post.

Absolutely. I didn't overlook that, just wanted to make sure, 'cuz I've seen a few stores that will trip you up on the electrical parts thing.

Spector_Ray · #19 03-23-2008, 01:26 PM

A fuel filter's a cheap part and doesn't hurt to change something like that. You'll eventually need a new one so now's a good a time as any.

Mike Money · #20 03-23-2008, 02:45 PM

I'd start cheap.

Fuel filter.

But then again, a lot of the newer cars have fuel filters in the tanks that are supposedly good forever.