Jump to content
Sign in to follow this  
TaterSalad

car problems

Recommended Posts

ok, i know this is a computer forum, but somehow computers and cars seem to go together:)

 

heres whats happening. i start my car cold, it idles around 1400rpms with a small pulse from 1400 to 1300. once it warms up it goes down to 900 for long enough that if your watching the tach you see it stop for a sec, then it goes down to 100rpms, goes back up to 900 then down to 100 over and over. then if i put it in gear it will stall out.

 

we have checked

-plugs

-plug wires

-cap

-roter

-bat connections

-grounds

-ignition

-vacume hoses

-pcv valve

-and for gasket leaks

 

tomorrow i will be getting a new fuel filter and trying that.

 

car is 93 mazda protege, automatic.

 

any ideas?

Share this post


Link to post
Share on other sites

Have you tried using some of that fuel injecter cleaner additive? It could be that your injectors have some crud build-up

 

Edit: And a new fuel filter would prolly be a good idea just as you said.

Share this post


Link to post
Share on other sites

Umm...what model car? Sounds a bit like a bad EGR valve. Are you experiencing any other symptoms like rich gas mixuture (tell tale sign would be black smoke out of the tail pipe), bad fuel economy, crappy response from the engine...etc?

Share this post


Link to post
Share on other sites
Also wouldn't hurt to check the air intake; sound as if it's being choked.
I second this.

 

My moms 06 Envoy XUV just had a bad intake valve and the same thing was happening

Share this post


Link to post
Share on other sites
Umm...what model car? Sounds a bit like a bad EGR valve. Are you experiencing any other symptoms like rich gas mixuture (tell tale sign would be black smoke out of the tail pipe), bad fuel economy, crappy response from the engine...etc?

 

car model was at the bottom of first post.

gas mixture is actualy lean not rich, probably checking the injectors tomorrow too. response is great, and smoke is clear once car is warm

 

Also wouldn't hurt to check the air intake; sound as if it's being choked.

 

checked that all the way through, air filter=about a month old, and still looks new, the rest had a tiny bit of grease in it that i only noticed because i wanted to find a problem

Share this post


Link to post
Share on other sites

My bad...i missed that. Check the EGR valve though...if it's not working correctly then it will act like one huge vacuum leak which is what it sounds like. You can probably just clean it out.

Share this post


Link to post
Share on other sites

ya, ive kinda thought about it, but because its only symptom is the (extreamly)rough idle i didnt give it much thought.

one more thing to look at tomorrow!

 

edit*

Check for vaccum leaks. Sometimes Ford/Mazda use vaccum to do stupid things in their cars.

have checked those when i checked the hoses

Share this post


Link to post
Share on other sites

It's the IAC ...

 

Idle Air Controller...when it goes bad the idle speed oscilates...up and down...

 

Pull the IAC out and clean the orfice of debris and try to reset it...if that dont work you will need to replace it....A quick internet search will tell you how to trouble shoot and test the IAC soleniod...not a big issue...

 

A faulty MAS (mass air flow sensor) or a MAP (manifold absolute pressure) sensor and make a IAC act crazy...

 

Usually the IAC valve get coroded with junk from air cleaners being in longer than they should have...

Share this post


Link to post
Share on other sites

Is there a service engine or check engine light on?

 

Most times it will end up being a crack in one of the folds of the intake tube leading to the engine bringing in unmetered air and a resulting lean condition.

 

How does the engine run when it is at high idle or when you power brake it to keep it running. Is it hitting on all cylinders at this point?

 

Edit: Looks like bowtie and I found a thread where we can do some work.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...