shupe

iTrader: (7)

Have a ’99 Silverado 5.3. Have been running a 89/91 duel fuel tune. Truck has a power loss around 3000 RPM when at WOT or close to WOT (not every time just some times). Tuner suspects it’s the TC locking up. ( this was here before and after new trail blazer tc install) Could be for all I know although it seems like it falls on its face similar to my old 88’ Integra with a hundred million miles on it when the A/C would turn on.

Tuner didn’t seem too helpful or interested in troubleshooting with out logging data. If I have to purchase logging software on top of the price of the tune I might as well as bought some programming software and enabled myself. I have purchased and installed a aeroforce scan gauge recently. I know it has logging data capabilities, can I use this to log any of the O2 sensor / mass air flow sensor data?

Anyone have any ideas? Is this a flat spot in the ’99 5.3’s power band or is the TC locking making my truck accelerate like crap.

I have a few issues I’d like to get identified before I start sending PCM’s back and forth paying International shipping.

12secSS

iTrader: (30)

Can't really say, it could be a multitude of things. Your best bet is to log any parameter you can. During acceleration, if the TCC is locking up, you would feel a slight load on the engine, yet the MPH would increase. Kind of hard to describe, but it would not feel like a bog. Find someone local that can look at your tune, or at least be willing to scan it for you with either HPTuners or a similar scanner.

FarmTruc

iTrader: (5)

See if any KR is showing up in that area, the 99 PCM's are prone to it.

If there is, just have your tuner desensitize the KS's a little. This very common on the 99/00pcm's, but can be fixed easily.

OR,

Check your front O2's at wot, to be safe, ensure they are around 880mv at wot around the mid range.

good luck,
allen

shupe

iTrader: (7)

Looks like the problem might be evolving or I have a few issues to work thought. Ove the weekend I began getting the P1133 and a P1153 indicating the HO2S switching. Truck is running like a dog! Have a hard time believing both O2s are failing at the same time. Read quite a bit over on tech. and came up with a few ideas.

Sounds as though rear co2 from a vet might help with the longtubes lack of heat problem. Or possibly the MAF sensor is faulty or in need of cleaning.

Any good way of testing the MAF sensor? I can monitor the MAF values though the aeroforce scan gauge. What should I look for?

Sprayed it down at lunch didn't notice any difference. Although the can of cleaner I bought didn't have the straw. The screen still looked a little dirty. Will grab a straw from a can of wd or somthing tonight. Unplugged the sensor truck fired up fine. From reading over at tech that some year modles of cars will run while others will not. One noted that the pcm would default to speed density (?) and run fine while others would run like crap.

Any ideas???

Raffman

iTrader: (9)

Sounds like the same problem I have. Pretty sure it was the cats. Just pulled them off last night for the LT & ORY install. One seems more restrictive than the other when blew compressed air through it. Last time I drove it the boost gauge went up to 12lbs of boost another indication of plugged cats. Does your problem get worse when the cats are good and hot after a a couple of wot passes? When the engine was just warm and not running for long it was alright but then after awhile it fell on its face with a wot.

shupe

iTrader: (7)

Allen - have been watching the aeroforce scanner and haven't seen ANY knock reported.
Using the scan guage what value should I be watching to check 02's.