Mechanics

FUEL INJECTION OR IGNITION PROBLEM

1999 Dodge Caravan

Engine Performance problem
1999 Dodge Caravan 4 cyl Two Wheel Drive Automatic 235, 00 miles

Fuel injection or ignition problem
suspected cause are sensors
but I do not know which one(s).


Dodge Caravan 1999 2.4 L
235,000 miles
Van has been running well (plenty of power) with low oil consumption
and just little higher gas consumption than when purchased.
I would go through second timing belt replacement this year if it were not for the
serious rust that is now showing up on hood, sides and rear. Because the
van still has so much power and carries my canoe, I would like to use it one
more year.
The only major problems the van had was replacing front wheel
bearings.

The current problem has apparently been developing for some time.
A year ago I replaced the fuel filter. Six months ago, the car started
to stumble on acceleration. I replaced the air filter.
Four months ago trouble code P0442 showed up.
Three months ago code P0455 appeared and the engine light went on.
I looked for a leak in the evap circuit hoses, but could not find one.
Online advice was to go through a smoke check.

Two months ago, I took the van to a repair shop to find the leak and
give me a NYS inspection. The repair shop determined the need for
- replacement of gas tank filling pipe,
- fix engine misfire at spark plug 1.

I did not believe the filling pipe needed replacement (and took an
inspection rejection). I replaced the gas tank cap, spark plugs and the
throttle position sensor. The engine light went off. Replacement of the
throttle position sensor did wonders for the acceleration problem.

A month ago, I heard a noise in the left front wheel, and discovered that
the brake pad had completely worn out and made groves in the
rotor (which the repair shop had failed to see during inspection).
I had replaced the left wheel brake pads and rotor two years
ago. The right front brake pads were fine. So this time, I replaced
the caliper, as well as brake pads and rotor on the front left wheel.
I suspect that the seized front left brake was the underlining cause
of stumbling problem because to start going I had to accelerate
a great deal more than usual.


Two weeks ago, the acceleration problem reappeared.
It happens especially when I have to accelerate after slowing down.
Most typically when, after driving on a major road, I have to turn
into a side street going uphill. To turn, I have to slow down. But to go
uphill I have to accelerate right after slowing down. Then the
van starts to stumble (i.E. Lose power and surge), if I accelerate
more the van goes a little faster but also stumbles more, and
engine light starts blipping and stays on. The latest trouble code
is P0301. However, if I stop completely before going uphill, and start again,
the van goes uphill with a plenty of power and no stumbling.
Once the stumbling starts it also occurs at speeds between
35 and 45 miles per hour. Above 50 miles per hour, the van
rides smoothly.

The next day, the van starts with no problem and drives fine.
This is the reason why I suspect that a sensor causes the
PCM to shift into a mode that does not take into account the
throttle position sensor, and the lean fuel-air mixture causes
a misfire.

Please let me know if you think the problem is with sensors,
or some other component. Thanks.
Avatar
Petroff
September 4, 2009.



You have a misfire on cylinder no. 1 check the sparkplug, compression and injector for this cyl. And also the following below: Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Rasmataz
Sep 4, 2009.