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Hi guys,
Ive got a 2002 Mitsubishi Eclipse Spyder GT 3.0 with 260k miles, manual tranny, cold air intake, everything else stock. Having a performance issue of sorts: Every once in a while, and I mean maybe once or twice a week, the engine seems to stall completely out for a literal half a second. Not enough time to kill the engine, but enough to feel the complete loss of power. It has happened at 60-80 mph cruising and it feels like a hiccup, and have had it happen as Im accelerating through 2nd gear and it feels like I just slammed my head into the steering wheel because at one moment you are pushed back into the seat under acceleration, and the next the total loss of power then right back into accelerating again like nothing happened. Ive taken it to several different very accommodating shops, and they cant repeat it, and I cant repeat it either for that matter, it just all of a sudden sneaks up on the old girl once in a blue moon. I just went thru and replaced all 4 O2 sensors and a cat, and I cleaned out the throttle body and MAS (had an emissions test and was throwing O2 and cat codes), but it did this before I did those things to it as well. Any ideas?
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Could possibly be something with the Throttle Position Sensor or its wiring… Also may be good to check battery connections and grounds to ensure they are clean and tight.
-Karl
Battery connections are good. MAYBE be a TPS, but as I said its VERY intermittent and I would think I would get an OBD code for that, and I put a LOT of miles on my vehicles during the week, and it will only hiccup once and every so often twice. I’d be inclined to think it would be more of a wiring issue, but as far as from alternator to coil to plug wires I cant see anything wrong with them from a worn-out perspective. The only other weird part is that it has ONLY happened while cruising in 5th gear, or accelerating in 2nd gear. No other times.
with Karl on this one, sometimes those throttle position sensors can be tricky, when you shift down i am guessing you are putting the power too it 😉 that being said you are adjusting the throttle position too pour the coals on so the throttle position sensor could be trippy, and nothing hurts in checking your connections too your battery and your grounds….
There’s fuel cut for over reving but it happening during cruise rules that out. Does it happen when you hit a bump? Any codes?
It could also be an issue with your MAF sensor. If you have a pretty cheap intake on the car then it’s entirely possible for the MAF to be getting bad readings, although this would throw a code. Since this is an intermittent problem, I’m going to guess that you have pending codes stored. What that basically means is that your problem hasn’t actually screwed up enough to set off a check engine light but you ARE throwing codes.
I would try to find a local shop with a high end scanner like a MODIS or another brand’s equivalent. If that fails then you could try the dealer as well since they’ll for sure have good scanner equipment, though they’ll be more expensive. The diagnostic charges for this stuff don’t sound very appealing, but it’ll probably end up being cheaper than throwing parts at it until something hits.
If you don’t have any codes, I might check the ignition switch. If it was a battery problem I don’t think it would effect performance that way. You can actually remove the battery cables while the engine is running and it will stay running. Not recommended, but it does happen. That said, the ignition switch can cut out the whole system similar to what you describe. If you see the instrument cluster light up for a brief moment this is where I might go with this. If not, you might look into the TPS theory but if that were the case I would think you’d have a CEL for it.
More info on solving performance problems here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and keep us posted.
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