150k miles - time for a tune up?

[Spinman]

Have a '96 Aurora with 150,000 miles (original owner)
Replaced plugs at 80,00 miles.
Recently hard to start - backfires - drivability issues on hills.

*********************

I started getting a very ocassional backfire when starting the car about 6 months ago.

Two months ago - the car started to exhibit "difficulity" when climbing a hill in OD - almost as if surging or hesitating. When I downshift into 3rd - everything is fine. Don't know if this is a transmission, ignition or fuel issue. My transmission guy says that I need to fix the backfire issue 1st - it may not be transmission related. Maybe ignition or fuel related.

Two nights ago - left the car outside for 4 days (coldest weekend of the year so far @ 5 degrees overnight). When I went to get the car - it would not start. Crank, Crank, Crank - backfire. Crank, Crank, Crank - backfire.

I could hear the fuel pump turn on and off when I switched the ignition on. I assume that pressure is OK -

Returned today with jumper cables, and after some cranking, and 2 backfires - it started. Restarted several times during the day fine. Ran fine once it started. As the temperature started to drop at night, the crank time increased and had 2 backfires during cranking.

The Service Engine light is not on, and has not been on. I assume that there are no stored codes. Original OEM Battery - going on 12 years.

******************

1) Should I replace the OEM wire set due to mileage / age? Is there a way for the home mechanic to test each wire to see if good or bad? I assume AC-Delco 748K wire set should be specified - I've read many post that generic or 3rd party cable cause problems.

2) I used Bosch plugs when last changed. Any recommendations? Stick with AC-Delco (41-950 or 14)?

3) Is there a say for the home mechanic to test the coil packs to see if they are good or bad? I've read posts that said they were getting "spark" even with a bad coil pack.

Other thoughts?

Thanks -

[03impala9c1]

Plug wires usually have a life of 100000 miles from the factory before they start corroding and jumping wires. REPLACE THEM.

Batterys usually have a life span of less than 5 years. I would recommend replacing that as well.

I would replace the plugs with simple AutoLite Platinums, its probably due time for those as well.

coil packs can be tested with a DVOM (Digital Voltage Ohm Meter). You can easily test GM coils by two steps. Select Ohm reading on the DVOM. You will see an omega symbol on the DVOM, thats resistance readings. first, you have twin pack coils, meaning two cylinders are controlled by one coil, meaning you have a set of four coil packs. You simply pull off the plug wires, and stick each prong into the terminals where the plugs mount on the coils, do one coil at a time and record the resistances between the two terminals on each coil. If there is a noticable difference between coils, replace the coil(s) that has the highest resistance. If you want to go further, you can pull each coil pack off the ignition module and test the contacts on the bottom of the coil.

If all of this does not solve the problem, you might want to have the ignition module tested at your local parts store. Make sure they test it at least three times, as it may pass the test the first few trys!

I have seen Fords with coils that tested fine though unless the engine was put under load, and that required a manufacturer specific scan tool to find out which cylinder would miss the worst.

Good Luck!

[03impala9c1]

I would also STRONGLY recommed replacing your fuel filter!

[Autobanaurora]

Hey Impala C, that's a sharp Aurora! I'm about to repaint mine....