1999 C1500 GMC Suburban 5.7 fuel issue

[HotWheelsBurban]

Keeping up with general maintenance is a good start, particularly if you're not the first owner. We bought our '99 Burb ten years ago, and that's what I have done (or in some cases, had done) with it. So far, so good, though since I got my crew cab we haven't driven the Burb a lot. Big truck has functional AC and heat, and the Burb was in the collision repair shop for a while last year too.

 

[Mister1500]

Mail is no issue. I was thinking more about PCM programming or deleting ie:EGR DELTE etc for more power or fewer overall issues

 

[Mister1500]

Maint not mail. Stupid spell check! LOL

 

[HotWheelsBurban]

Mail is no issue. I was thinking more about PCM programming or deleting ie:EGR DELTE etc for more power or fewer overall issues

I haven't done any of that on my trucks, just the Passlock delete on the Burb. My crew cab is a '97 so it doesn't have that(another reason besides the 5.7 L31, and its low mileage, that I was interested in this truck!).

 

[df2x4]

If you're sending the PCM out to be programmed, I've been very happy with the Black Bear Performance standard mail order performance tune on my red '97. Made a big difference in power and how the truck felt in general. You can have them tune the PCM for higher octane fuel if you want a little more as well, but even the 87 octane tune is a big improvement over stock.

One word of warning, since you have a 4L60E I would instruct them to leave all transmission parameters as they are from the factory. Messing with that stuff sent me down a long and expensive road that eventually lead to a 4L80E swap.

 

[Schurkey]

If you're in CA, or a state with CA-type rules, none of the computer tuning is going to be legal, and they'll catch you next time it's inspected.

If you're not going to get caught, I'd have the speed-limiter removed, too.

 

[df2x4]

^ Excellent points.

 

[Spareparts]

Could you have a PCM for emissions testing and another tuned for performance to swap around?

 

[df2x4]

Could you have a PCM for emissions testing and another tuned for performance to swap around?

If you pay the PCM core charge ($125) from Black Bear, they'll send you the tuned PCM and you can keep your stock one. That's what I did, but eventually had them reflash the stock PCM to another tune after my transmission swap. Kind of wish I'd kept the stock one unmodified...

EDIT - Added bonus of doing this is that the truck won't have any down time waiting for the tuned PCM, or if you ever need to send it back for changes you can swap the stock one in.

 

[Mister1500]

Great advice; I live in Indy, no emission testing here, and I’ll never be crazy enough to live in a state like CA! Long live the mighty V8!