Question about 1995 GMC Sonoma
My 1997 Suburban began to lose power so I checked the fuel filter which was clogged so I replaced. While at the parts store they had sale on plugs so I figured at 155000 I should and did replace. I also ran some seafoam through as well. The next day the truck perfect. I pulled a 20 ft enclosed trailer at 75 mph no prblem....for about 150 miles. All of the sudden it was like you threw out an anchor. I lost almost all my power. It would run normal power up to about 1/8 - 1/4 throttle but after that it would just bog down and make popping sounds. I pulled over checked my fuel filter and fuel cap...both fine. I unhooked my battery for 5 mins and hooked back up...PROBLEM SOLVED!!! I made it another 50 miles until it happened again. Went through this the entire 400 mile round trip and everytime I unhooked the battery it would run normal and the check engine light would go off. Since then I have replaced the O2 sensors, had the catalytic converters and muffler checked. I cleaned the EGR and mass airflow sensors (with proper cleaners). Nothing changed. I forgot to mention that after I unhook and reconnect battery it would run 150 times better however not perfect. It would hesitate when first accellerating from stop and would not have full power if you put the accellerator pedal to the floor. Anyway, I swapped the mass airflow sensor from my dads 98 Chevy to see if that was a problem. His truck ran very poorly so he purchased a new one which fixed the problem which leads me to believe mine was bad. With his MAF on my truck it ran really well...I still had a hesitation, but this was the first time since this all started that I was able to achieve full power....for a few days till it went back to its normal behavior. By the way when the check engine light comes on the codes that show up are "bank 1 and bank 2 too lean". I have perfect fuel pressure and have replaced the cap and rotor as well. Any ideas?
I just went through this with a ford at the shop we threw parts at this car for days. It turned out to be the PCM. You can have all the best fuel pressures plugs, and MAF input but if the computer isn't reading it properly it can't work properly. The batterybeing disconnected is resetting the PCM taking it out of limp mode thats why it runs ok for short bursts. Its probably over-heating.
Posted on Feb 01, 2009
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