Time for Tune Up?

[92ExpJunkie]

I just recently bought a 1992 Explorer XLT... odo reads about 92k (possibly 192k+ ?). Anyhow, I haven't had many issues with it since I bought it about a week ago. It ran smooth during test drive, everything was in working order. But I noticed as of yesterday, after a good 100 mile trek from my old home to where I am moving, that now when I accelerate, I hear a slight knocking sound. I don't hear it when I'm on the brake, but when I gas it, its definitely noticeable. Also, I've noticed along with this, that when I drop it into park, it has a rough, bubbly kind of idle. I don't know if the owner before me maintained it very well, but I'm just curious if its just that time for a tune up, or is there something else I should be looking for? I don't have any tools of my own, so pulling things apart is impossible for me right now. Any help would be awesome.

 

[Anime]

If it knocks when accelerating hard, it might be anything from dirty fuel injectors to a fuel issue or even a dirty mass airflow sensor. Sometimes old spark plug wires will cause hesitation on acceleration, and replacing them with good ones will make a noticeable improvement. New plugs make a pretty big difference too.

Since it's new to you, your best bet is probably to at least pull the plugs to inspect them. These engines seem to idle smoothest and run best with the Motorcraft plugs, so if they need replacing that's what I'd suggest.

You should also check up on the regular maintenance items (air filter, fuel filter, oil change, etc.) to be sure it's in top shape.

As for tools, I'd suggest picking up the $299 Craftsman set that comes in the 3-drawer plastic case from Sears when it goes on sale for ~$150. Heck of a deal for tools with a lifetime warranty and storage included. You'll wind up picking up specialty tools as you go along and find out about various maintenance items you can easily do yourself.

 

[nugs]

If it knocks when accelerating hard, it might be anything from dirty fuel injectors to a fuel issue or even a dirty mass airflow sensor. Sometimes old spark plug wires will cause hesitation on acceleration, and replacing them with good ones will make a noticeable improvement. New plugs make a pretty big difference too.

Since it's new to you, your best bet is probably to at least pull the plugs to inspect them. These engines seem to idle smoothest and run best with the Motorcraft plugs, so if they need replacing that's what I'd suggest.

You should also check up on the regular maintenance items (air filter, fuel filter, oil change, etc.) to be sure it's in top shape.

As for tools, I'd suggest picking up the $299 Craftsman set that comes in the 3-drawer plastic case from Sears when it goes on sale for ~$150. Heck of a deal for tools with a lifetime warranty and storage included. You'll wind up picking up specialty tools as you go along and find out about various maintenance items you can easily do yourself.

i bought the set 2 months ago for 159

 

[92exp4x4]

Congrats on your purchase. When I get a new-to-me vehicle, I go through it with a fine tooth comb.

1. I fix any non working stuff noted on the test drive, then I pressure wash the hell out of it. This makes it much more pleasent to work on, then I..

2. Change all fluids. Engine oil and filter, flush out and change coolant and thermostat, flush the transmission and transfer case (4x4), change brake fluid, change power steering fluid and change the oil in the axles.

3. I then give it a major tune up; plugs, wires, air filter, PCV valve, fuel filter, then add some fuel injector cleaner to the fuel tank. I clean the MAF sensor, IAC valve, and the throttle body and plate.

This may be a little excessive and somewhat expensive at first, but all my vehicles are purchased with the intention of keeping them long term. This is a good start for long term use of your used vehicle. Its a great chance to get to know your new purchase too. Most of the work you can do yourself with basic hand tools. I do all the work myself except flush the transmission as I do not have the machine to do it.

Try at least number 3, to help with the knocking sound. What you are hearing is most likely pre-ignition or pinging as its more commonly known. Its a fairly common problem with these early explorers. Search the forum, you will find tons of info on it.