Car surges badly under part throttle in closed loop
#1
Car surges badly under part throttle in closed loop
Just as the title says, it surges, hesitates and bucks under light or medium throttle. WOT is fine. Its done this ever since I put the engine together, so I usually run it in open loop with the o2's disconnected. At idle the car smells filthy rich (even with the o2's plugged in). Well at work today I decided to hook up my scan tool and look at a few things with the o2's plugged in. Under part throttle, the long term fuel trim counts drop to 110-115 and it hesitates and bucks. Once i let the engine idle, it runs kinda bad untill the LT fuel rises to about 128 and then it idles fine. Is this some sort of a tune problem? I had it tuned from pcmforless. My o2 sensors are one year old, and they are bosch... maybe thats the problem. Anyone help me out?
#2
I have heard from lots of people to only use AC Delco O2's because the aftermarket ones can have all sorts of problems. They are like $35-40 each on Ebay. Well worth the little extra to have the piece of mind.
#3
I just got a tune from them too, and imm experiencing the same type of problems. When I accelerate anything less than wot, instead of the power being a smooth linear increase, it kinda surges. Im working w/ him now to fix it. I hope we can.
#4
make sure you guys check your spark plugs... i had this same problem when i had new plugs and wires installed by a **** poor shop (Burkart Automotive, yes the same burkarts that run the funny car) and they installed my #6 and #8 cylinder spark plugs with absolutly no gap... car bucked like mad when i was just trying to cruise but pulled fine at WOT
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