OBDII device

[Sid Hoffman]

It's less than the cost of one shop trip, and modern computers are remarkably good about telling you exactly what they're unhappy with.

Sadly the older ones are not quite so good.  I have a 97 Ford that I spent months tinkering with trying to address a hesitation problem and during that whole time, I could never get it to throw a code.  The problem diminished as the weather got colder and it hasn't warmed up enough yet for the problem to return.  Perhaps in another month or two I'll figure out what to do.  I'm still undecided on if I even want to keep my current car or not, as it's an $1800 craigslist special that has had its share of problems for sure, and I haven't even owned it a full year yet.

I do have Torque Pro, although my old $20 ELM327 burned out last year.  I also have an old Scangauge, which works but is much more limited than Torque Pro with an appropriate adapter.  I'll have to decide this spring what my plan of action is.  Part of me really wants to pick up the OBDLink MX and resume troubleshooting if the problem recurs, but OTOH I'm also kind of tired of pouring money down a hole, or so it feels with this car.

[DollarBill]

It's less than the cost of one shop trip, and modern computers are remarkably good about telling you exactly what they're unhappy with.

Sadly the older ones are not quite so good.  I have a 97 Ford that I spent months tinkering with trying to address a hesitation problem and during that whole time, I could never get it to throw a code.  The problem diminished as the weather got colder and it hasn't warmed up enough yet for the problem to return.  Perhaps in another month or two I'll figure out what to do.  I'm still undecided on if I even want to keep my current car or not, as it's an $1800 craigslist special that has had its share of problems for sure, and I haven't even owned it a full year yet.

I do have Torque Pro, although my old $20 ELM327 burned out last year.  I also have an old Scangauge, which works but is much more limited than Torque Pro with an appropriate adapter.  I'll have to decide this spring what my plan of action is.  Part of me really wants to pick up the OBDLink MX and resume troubleshooting if the problem recurs, but OTOH I'm also kind of tired of pouring money down a hole, or so it feels with this car.

Sounds like a throttle body valve plate sticking.

[Sid Hoffman]

Sounds like a throttle body valve plate sticking.

Yeah who knows.  I actually removed and disassembled the idle air control valve twice, spraying it down with whatever the parts cleaner stuff was that said it's safe for that type of part.  A little bit of black carbon stuff came off, but otherwise it was actually very clean already.  I also sprayed a bunch of parts cleaner all over the throttlebody itself.  The IAT and coolant temperature sensors appear to be good and reporting accurate numbers based on my OBD-II device.  The TPS returns good value, as does the MAF.  Oh yeah, cleaned and inspected the MAF too.  Fuel economy is good, which generally rules out a dramatic problem with the MAF or O2 sensors.  Replaced the spark plugs and wires, and verified the gap on the plugs before installing them.  Old plugs actually looked really good, which generally rules out an ignition problem.  It's tough, because everything I checked always looked good, and any time I replaced parts it ran the same.

Like I said though, at least with my car the problem went away when the temperatures dropped, so I'll just wait and see how it goes over time this spring as it starts getting warmer.  I still have to get an estimate for having the A/C fixed.  If that's affordable then I'll probably do it, but if the A/C is going to be $1500 or something, then I'm just going to ditch the car entirely and get something newer.

[a1smith]

Have you checked for vacuum leaks in your evaporative emissions system?  Also, check the operation of your evaporative emissions canister purge valve.