Next time it acts up, leave the engine running but stop and momentarily loosen the gas cap. If the running problem clears up, the vent in the cap may be stuck. That's real rare but it's always the first thing we think of. That might make the Check Engine light turn on too, and a diagnostic fault code "large evap leak detected" may be set. You can ignore that and it will erase automatically after starting the engine 50 times.
Sorry to say the throttle position sensor won't cause that problem either. Any bad connection, even intermittent, will turn the Check Engine light on and set a related code. If the sliding contact is making poor enough contact, you'll have a hesitation or stumble on acceleration. That can happen when speeding up, not just when leaving a stop sign.
Your description is sounding more and more like a plugged pickup screen in the gas tank. That isn't real common but when it does happen, it can be really hard to figure out. It happened on my '88 Grand Caravan a number of years ago. Took me four hours to nurse it all the way through Minneapolis road construction, but once I got on the highway and kept it over 55 mph, it ran fine for over 150 miles until I had to slow down for my turn-off, then it stalled again. Knowing now what the cause was, a clue would have been found by unplugging the vacuum hose from the fuel pressure regulator and plugging it. That would have caused fuel pressure to go up and there would likely have been a little black smoke from the exhaust, but the increased restriction would have reduced the amount of fuel being pumped and that needed to get through that sock in the tank. The more immediate clue is the faster you drive, the better it runs. Also, it takes a little while for that pickup sock to collapse and become blocked. 30 miles is just the right amount of time for that to show up. Once the problem acts up, it will stretch back out and open up if you let it sit for 10 or 15 minutes with the engine off, then it will run fine again for a few minutes.
Has anyone checked for stored diagnostic fault codes yet?
Saturday, October 15th, 2011 AT 11:38 PM