What kind of CAT back setup??? You might have gone too big on the CAT back,
causing too little back pressure.
I've done this, and you'll notice you're truck will run great from 3000-4500
rpm (pulls like mad), but down low you've lost the real pulling power it use
to have. If this is the case, and you have the Mopar Performance headers,
I'd say switch out the muffler for a super turbo. I did this, and gained
back my mileage, plus the HP increase was around 10-15 hp (rear wheel). I
was able to get 219 hp total at the rear wheels with Doug T. headers, 3"
in/out CAT, and super turbo muffler. I was around 205 with the same setup
(except with Ultra FLO). The 3"in/out cat was my latest change, and it
didn't work well with the Ultra FLO & headers.
Hope this helps,
Sam '00 RT
> -----Original Message-----
> From: owner-dakota-truck@buffnet.net
> [mailto:owner-dakota-truck@buffnet.net]On Behalf Of Greg Abbott
> Sent: Monday, January 17, 2000 7:51 AM
> To: Dakota Mail List
> Subject: DML: Decreasing Mileage
>
>
>
> 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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