Hesitation, Stalling and Backfire

From: DakotaPU93@aol.com
Date: Tue Feb 04 2003 - 22:26:07 EST


Hi DML -
I am the original owner of a 1993 Dodge Dakota, 3.9L, V6, 5-speed
with ~ 185K miles.

This past summer my truck started hesitating. Towards the fall it got
progressively
worse but still very drivable with backfiring coming from I believe the #5
cylinder.
Shortly thereafter and with the onset of the below freezing temps in the
Northeast it
would stall in the morning if not warmed up.

Below is a detailed explanation of the SYMPTOMS + a log of the maintenance I
have performed as well as a private garage.

Thanks for your help...

When the truck is first started up after sitting all night it hesitates and
backfires.
Just recently it also has been stalling when coming to a stop. Then it
either starts or takes 5 minutes to restart.
If I rev the engine when coming to a stop it doesn't stall.
If I get on the highway during the first 5 - 8 minutes (before warm-up) it
actually sounds as if the engine cuts in and out as if gas is not getting to
the engine or being blocked.

After 5 - 8 minutes of driving the engine is usually OK. Only minor
hesitation, and backfiring - NO more stalling.

I'm wondering if my fuel injectors are shot? Or if my timing is off?
Or something else?

I performed the following maintenance over the past months to hopefully
improve the performance but none seemed to have helped.

The problem initially started in the May/June 2002 timeframe but not that
noticeable. It has gotten progressively worse.

I drive ~ 15,000 miles a year.

Oct 1, 2001 spark plugs, air filter

July 28, 2002 replaced fuel filter
tried 2 applications of STP fuel injector cleaner

Sep 14, 2002 replaced cap, rotor, wires, PCV Valve, Breather Element

Nov 30, 2002 tried another application of STP fuel injector cleaner

I checked my check engine codes and they dont indicate any problems.

After having no other ideas I brought it to a garage this past week.
Their computer said my fuel pressure was 51 pounds, I guess it should have
been inbetween 28 and 32 pounds. He changed the fuel pressure regulator and
the retest
indicated the fuel pressure is in the correct range now. He also
administered a
fuel injection cleaning with a professional machine (hooked it to the fuel
line, disconnected fuel pump, etc) Also included in that was cleaning of the
throttle plate and idle control.
The result is that the backfiring situation is much better, it will still
occasionally backfire but not as severe or as often. The stalling after a
cold start and hesitation and rough running on highway are still evident.

Other bits of info: Original muffler and original catalytic converter

Any help or advice would be greatly appreciated.
Thanks, Kev



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