The Catback System and Air Filter can not "break" the PCM or O2 sensors
unless there was a pre-existing problem that was overlooked. As for the
Headers, if the O2 sensors were damaged on the installation it is possible
that they might have contributed to the poor mileage. Did you reset the
computer initially after the modifications were installed? Also, were any
of the vacuum hoses accidentally pulled off during the modification installs?
You noted that you installed a USED PCM after the original died and that's
when the O2 sensors read as bad. Sounds like it might have been a bad,
used PCM.
- Bernd
At 09:51 AM 01/17/2000 -0600, you wrote:
>Recently purchased a Dakota 4X4 auto with 5.2L engine. Put the K&N
>filter, headers, and cat back on. Multiple problems
>have come up:
>
> 1. Prior to mods, I got about 17-18 mpg on the road over a long
>trip. After the mods I got 15.
>
> 2. Shortly after the mods went in, the PCM died.
>
> 3. Upon putting in a used PCM, the up and downstream O2 sensors
>read as bad.
>
> 4. Now the mileage is 11-12 mpg.
>
>Any suggestions as to what is going on? Research prior to the mods
>suggested at least no change and probably some
>improvement. Could the mods damage the O2 sensor (all mods are MP)?
>Did I get a bad used computer? Any way to tell?
>
>The dealer I purchased from gave a 6 month warranty and he is standing
>by that well. He is thinking, though, that the mods are
>contributing to the problem. What is a reasonable mileage figure for a
>40k truck with these mods?
>
>Thanks!!
>
>Greg
>
>
>
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