Momentary loss of power when accelerating
OK, this is a 97 Eclipse GS-T, mostly stock, automatic transmission. For the last month, I'm getting a momentary loss of power when I accelerate from a steady speed. No CEL's, just a hesitation that is more severe the more I depress the accelerator pedal. Once the car reaches the speed I want and let off the pedal slightly, the car runs normally (I've had it up over 100 mph). I guess I'd call it "bogging under acceleration", definitely doesn't appear to be turbo lag, I'm familiar with that, I've driven the car for 11 years.
One thing that WILL produce a CEL is flooring the accelerator at expressway speed when passing. P303 reports a misfire (the engine stumbles, then recovers, running normally when I back off the pedal). Once I clear the CEL using my ScanGauge II trip computer, everything is normal as long as I don't floor it again. Could the knock sensor retarding the timing be causing this stumble under heavy acceleration? Not sure how good the octane of the gas around here actually is.
I just checked the transmission fluid, looks good. The car has 141,000 miles, and I had the fluid changed at around 98,000 (bought the car with 64,000). Spark plugs were changed about 3 months ago, using the recommended NGK BPR6ES plugs, properly gapped.
The only change that happened just prior to the issue appearing was replacement of the alternator, which is outputting about 14 volts at cruising speed.
One other odd thing- when I pull out of my driveway (cold start), the car has a serious lack of power for about 200 feet, it's hard to do the 25 mph street limit (mild uphill grade), then suddenly the turbo kicks-in and I must quickly back off the throttle. From that point, the engine's power seems to be normal, other than the hesitation. Never previously had this cold start issue, it coincides with the hesitation issue when accelerating from a constant speed.
Any ideas? None of the symptoms occurred prior to about two months ago, the stumble on heavy acceleration (and CEL) was the first to occur.
143K not-so-daily driver, now that I'm retired. Last fall had the convertible top replaced (second time since I bought the car in '07). Also had most of the body repainted (peeling clearcoat) by a first-class bodyshop. Took five weeks, for a total cost for both jobs of $4K. Car looks almost new now. BTW, damn tired of seeing the obnoxious Eclipse Cross commercials. It's heresy using the Eclipse name on a damn SUV.