Miss at 5 K
 

I was doing a 3 dayer at Mid Ohio and my 2.5 had miss at 5 K. The tach redlines at apx 6400 so I would think the engine should run smooth to at least 6400 before the rev limiter kicks in. It is a 99 2.5 that is strictly stock. Any help about what this might be and what steps to correct this. The miss seemed to be more noticeable in 3rd gear than in 4th. Bill

hook up some test equiptment

CEL on? Error codes are? Mileage? Original MAF? Any recent repairs done?

I just had it scanned and it came up 1128 and 1130. The CEL is on of course. This happended to me last month at Watkins Glen, but the CEL light went off on its own. 82500 K miles and I do not know if the MAF or throttle body has been changed or serviced. It runs fine around town, but when I push it at the track it cuts out at 5K. The engine must be in great shape, I did a 8400 mile trip in Febraury and did not use a drop of oil. This weekend at Mid Ohio I just shifted at 5K and drove it like that, it ran great but I know it should be better I would imagine. I think a should be shifting around 6K. Thank you, Bill

P1128 Oxygen Sensing Adaptation, Idle Range, Bank 1 – Above Limit
P1130 Oxygen Sensing Adaptation, Idle Range, Bank 2 – Above Limit
Possible fault causes:
– Incorrect signal from MAF sensor
– Intake air system leaking
– Fuel pressure too low
– Volume supply of fuel pump too low
– Fuel injectors fouled
– Exhaust system leaking

Bottom Line - Your car is running lean. In most cases we are looking at an intake air leak or a bad MAF. If the MAF is bad then it is sending the wrong signal to the DME. Driving with these fault codes over time could damage your cats or worse.