Well, I'm at work right now but the wife just called and said the car was running really rough. "Shaking while driving" were the words she used. She pulled over, turned it off, and called the tow truck. Now it will crank but no start.

This was all of a sudden, no recent indications. I'm going through a probability list in my head for this evening when I start diagnosis. Here's what I'm thinking:
- fuel filter
- fuel pump
- valve/sensor related
- timing belt and/or pulleys

Any other thoughts come to mind? How would you go about diagnosing...
[2003 Protege 2.0 L approx 165,000 KM]

EDIT: Tow truck operator got it going by stepping on the gas pedal and starting...thinks its a fuel filter but I'm pretty sure he didn't investigate very much. Sounds like fuel starvation is a good possibility though

EDIT 2: Ducked out of work to take a look and it started up, very rough idle. Revs up and down, up and down, around 800 rpm (very low) and near stall when I shift. Seems to be better if I step on the gas but still rough.

 

Need some history:
1) Last time spark plugs changed
2) Last time PCV valve changed
3) Ever put in fuel system cleaner
4) Check engine light on or flashing
5) Ever clean throttle body or MAF sensor
6) Ever flush and fill coolant
7) Need to inspect for vaccuum leaks, cracks
8) possible flooding due to leaky injectors

 

1. 4-5 yrs
2. Likely never
3. No
4. No CEL
5. No
6. Yes
7. ok
8. ok

 

1) Time to install new plugs and ignition coils.
2) Install new PCV valve and attaching hose (Mazda never would have inspected this or changed this!!!!!!!!!!!)
3) Need to put fuel system cleaner in right now and at least once/year
4) no cel is weird
5) A must to clean throttle body and intake. Disconnect negative terminal on battery followed by a few applications of brake pedal to drain any current lurking around and re-set computer. Try to catch the dirty fluid when spraying the throttle body by slightly removing throttle body. Install new throttle body gasket. Remove MAF sensor and liberally spray it, shaking it with your arm a few times to help it dry. When done your work and all is dry, re-start vehicle and let idle for 10 minutes before driving.
6) Coolant should be flushed and filled every 2-4 years to help cooling sensor from corroding sending bad signals.
7) inspect vac leaks
8) don't worry about actual fuel injectors until all of above is done first

Bonus: Clean EGR if possible, may be do it when change plugs.

 

Ok I'll go grab the coils, plugs and pcv valve and change them today. But for it to die all of a sudden like that, no warning, makes me think that it isn't a dirty throttle body or EGR valve, but some sort of failure. Thoughts?

 

Thoughts: Have to do regular maintenance stuff first. A combination of them not working is not good. A vac leak, crack in intake tubing could really throw computer off. If it was real bad a cel would be thrown. Do all the regular maintenance things we should do first before moving ahead.

 

I agree with noggin.

 

Bought the coils, wires/boots, and plugs. But before I threw them in, I checked the throttle body and the ERG valve. Pics are attached. They both look a little carbon-y but I wouldn't think they are blocked.

One thing I am concerned about is the normal operation of the ERG valve. If I push it down, the spring does not pop back up. It's sticky and needs to be pulled up. Here's a video that shows what I mean:

 

as long as it's clean and moving you should be fine.

the positive back-pressure design has a hollow valve stem. This allows exhaust gas pressure to push against a spring loaded vacuum valve. When back pressure rises, such as on acceleration, exhaust pressure closes the spring-valve and seals the vacuum opening. This allows an engine vacuum to open the EGR valve.

From: AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - How Does an EGR Valve Work scroll down a bit

The EGR valve consists of a poppet valve and a vacuum diaphragm. When vacuum is applied to the EGR valve diaphragm, it pulls the valve open allowing exhaust to pass from the exhaust manifold into the intake manifold. Some engines have "positive backpressure" EGR valves, while others have "negative backpressure" EGR valves. Both types contain a second diaphragm that modulates the action of the valve. This prevents the valve from opening unless there is a certain level of exhaust backpressure in the system. EGR valves are calibrated for specific engine applications. The wrong valve may flow too much or not enough exhaust and cause emission, driveability and detonation problems.
FROM: http://autos.yahoo.com/maintain/repa...ques080_1.html

 

Unless I'm misunderstanding the readup in the EGR valve, the valve itself is springloaded. Since my spring doesn't pop the valve back up, it can't function correctly?

The 1st link says that when exhaust pressure is low (idle), the spring should keep the vacuum port open. If the valve is stick open it would cause rough idling.