Is it ok to drive a truck with a bad coil / spark plug?

Wow, I am so glad I asked you folks!

It's true I don't know much about cars. I almost didn't bother to ask you, because I thought it was unlikely to be a big deal. The only cars I have done significant work on have been from the 60s -- no injection, no cat. Only 3 moving parts.

I feel like I am never going to find a feckin' van.

Naio wrote:
One of the vans I am looking at (current top contender) had a misfire, now traced to a bad coil and fixed.

The seller is the type who did not notice the misfire. So I have no idea how long she was driving it like that. She just got back from a 2000 mile trip, anyway.

Does this matter?

YES.

raw or unburned fuel can and will cause problems, if not now, down the road. Cylinder wash is just one of the many potential problems..

Raw or unburned fuel WILL poison the cat converters and the OXY sensors.. Two generic cat converters at $300 plus labor each and 2 upstream OXY sensors at $50 each..

So, you could be in for $700 worth of parts plus labor due to premature raw fuel damage to the external parts..

I would "pass"..

carringb wrote:
Fords will shut off the injector once it sets the code, so there should not be any adverse affects.

No, does not.

Have had a bad COP, never set any lights, no codes just a low speed miss. Idled perfect but give it a bit of throttle and the miss would start and get worse up to about 45 MPH then even out a bit up to 55.

Only way I found out was to take to the Ford dealer, pay the diagnostic fees and with their OBD2 computer it gave the percentage of power imbalance between cylinders.

On another truck the dealer failed to properly torq the plugs and had a miss and raw fuel smell in the exhaust.. No codes and no light..

I retorqed the plugs, no more raw fuel smell in the exhaust.. BUT, after a few thousand miles I started getting codes set for one of the OXY sensors..

The raw fuel dumped, poisoned the OXY sensors..

carringb wrote:
Fords will shut off the injector once it sets the code, so there should not be any adverse affects.

My 97 F150 with a 5.4 had a miss and it did destroy the cat. Not sure if that early model had the fuel injector shut off or not?

I had to cut a relief in the exhaust just to get to the repair shop...100% clogged cat is no fun.

Thanks!

Jeremiah

Fords will shut off the injector once it sets the code, so there should not be any adverse affects.

I agree with others.

If they ran it on a 2000 mile trip with a dead cylinder, they probably didn't care about doing maintenance.

You don't have the mechanical knowledge or $ to buy a vehicle with a known problem and long term mis fire is/could ruin that cylinder.
Good job picking out the problem. Pass on that one though. In attentive lazy, uninformed previous owner = good chance that they didn't take care of the rest of it either.

Well as noted get a test of the engine, BUT, when did it start? You said she was on a 2k trip, but when did the miss start? Kinda hard to blame the woman for not noticing it, but how many guys are just as inept at taking care of stuff? Get a good checkup at a shop, check oil for gas smell maybe spend $25 for oil analysis if you really like the vehicle. My son has a f150, has 150000 on it the coil pac went out it started to miss, we ran the codes replaced the suspect, ended up buying another just after we replaced 1st. So no telling when the thing quit.

Detective work.... On a 2000 mile trip he was likely hitting pretty high speeds as well as accelerating and decelerating quickly at times. He'd have to be a real a_ _ not to notice a misfire, especially from a bad coil. Soooooooooo....... Just sayin. I am an eternal optimist who goes through life with very few concerns or worries so consider the source.

Get a compression test on all cylinders before buying it.