Life with the silver car continues, it’s been nearly two years since the first article, and I thought it was time for a follow-up. Things don’t seem to get better with age when it comes to most cars and this one is no exception.
Minor irritations also continue, first in the way of a failed HVAC control, seems the fan speed controller will only function in settings 3, 4, 5, and OFF. This isn’t a big deal in the winter, since the GTP’s heater struggles to keep the windows frost free on any setting lower than “5”, but in the summer it makes adjustment of the A/C quite bothersome and noisy. Replacement of the resistor is around $50 and an afternoon under the dashboard fiddling with Torx screws. However, if the problem lies in the actual heater controls finding a replacement dual-zone climate control panel could be very expensive.
Also during the summer, we had the passenger side window motor refuse to work. None of the switches wanted to respond until the door was given a good slam, likely the motor has a dead spot or the window track had somehow jammed. As of late it hasn’t happened again.
Something I forgot to mention in the first article was this vehicle’s propensity to digest headlight and driving lamp bulbs. I am reminded of this since I replaced yet another just a week ago. On average since owning this car, we’ve replaced a full set of 4 bulbs every 8 months or so. They don’t all go at once, so you have to keep an eye on them.
Most recently the GTP’s usually reasonable fuel economy has dropped into the pits. Typically, mixed City/Highway driving would return a modest 23-25 US MPG, currently we’re seeing 19-21 US MPG. When doing purely highway travel observing 29-32 MPG was not uncommon, but after a post tune-up 1000 km trip a few weekends ago, the best I could muster was 25 MPG, the engaging the cruise control would drop that number to 23.5.
Around the same time, we noticed the significant drop in fuel economy, the wife also noted a rough idle characteristic at times. It was completely random, but when sitting at a stop light or similar situation, the engine speed would drop to 500-600rpm and shudder or miss. Since the car was running on the factory plugs and wires that were nearing their recommended change interval, I sourced and installed replacements. I had suspected that the symptoms were indicative of a spark related issue. Pulling the plugs seemed to support this as well, 5 out of 6 were burned open to a .070” gap and the number 2 cylinder was fouled with a dry, black soot.
After the tune-up, the fuel economy failed to change at all.
Yesterday the car finally decided to give a peek into the situation when a “Check Engine” light illuminated. I knew this may either indicate our problem or may simply be playing Chicken Little about the gas cap seal, like it traditionally does any time the temperatures get a little chill.
The GTP was taken by the dealership to have the codes pulled and they reported the IAT sensor was out of range. The Intake Air Temperature Sensor being on the fritz could certainly account for terrible economy and drive-ability issues. When the car was brought home, it had set the Check Engine Light again; I yanked the little sensor out from the inlet tract for a look. Visually it appeared fine, and since I didn’t have the specs to bench test the unit, I gave it a few shots of contact cleaner and re-installed it. After a bit of test driving, the problem didn’t go away so I resolved to purchase a new sensor.
Cost on the new sensor was about $30 and I’ll install it later today, hopefully this fixes the issue. I’ll also have a look at the #2 spark plug again to check for fouling, if so I figure one of the coils could be underperforming and needing replacement.
For the record the car has just over 100,000 miles at this time, and I’m continually disappointed with these electrical related failures. On a high note, we plan to retire this car and replace it with a Ford Mustang of some sort in summer of 2011. So far it’s been a pretty silly ride, stay tuned for more updates as they occur.
Read the Entire Living with a Pontiac Series:
Looks Good on Paper:
UPDATE 1 –
UPDATE 2 –
Back in the Grind - Looks Good on Paper & Living with a Pontiac
