I read another recent thread where a 99 is having trouble accelerating. I don't know if this will be the same thing.
Sometimes when I accelerate my ranger hesitate or shakes a little. I have inspected the vacuum lines, and couldn't see anything. The plugs and wires only have about 55,000 miles on them, but I guess they could be giving me a problem. Any suggestions?
It has a 4 cyl.

 

I have the same issue, only mine has a few more miles. I've checked for a vacuum leak, but couldn't find one, and I'm sure the check engine light would come on if had any real issues. The only thing I've found to help is run premium fuel. Sounds funny, I know, but I imminently noticed a difference in the idle, the acceleration just off idle, and the overall performance. Mine would actually even ping just a bit on the freeway on a hot day. It may be worth running yours almost out, then put in some good gas. I know things are tight, and we all want to save a buck, so I always ran regular in mine. But so far it's worth the couple extra dollars, and it gets as good, if not better mileage since it's not struggling so much, and having to give it extra pedal to get it moving. At least that's my experience.....

 

Thanks, I will give it a try.
I have been running Mid Grade because of a pinging issue a few years back. I'll try Supreme next.
It is interesting that you mentioned yours pinged on a hot day. We are having some of our hottest weather ever and that's about when I really started noticing it. What does the hot weather do that contributes to the problem?

 

I think the heat both under the hood and ambient contribute to the fuel, lower grades especially, vaporizing, or simply becoming less stable. When the combustion chamber temp rises, poor grade gasoline cannot maintain it's composition and ignites from "hot spots" in the cylinder, not just the spark from the plug. Also as the road temps increase, and the undercar/underhood temps increase, the fuel tries to vaporize a bit, causing many problems. It's obviously much more complicated than that, but that's kinda the result.

 

Thanks again.
I will give the Supreme gas a try.
I believe that I may have a vacuum leak also, because when I put the AC on Max it starts to blow out of the defrost vent after I drive awhile. From what I have been told that is controlled by a vacuum and the actuator can't keep the vent in the correct position. Someone suggested a vacuum resevoir underneath the Air Filter might have a crack. Are you familiar with this problem?

 

A number of things can cause hesitation when we go at throttle up.

Acting out TPS, dirty MAF sensor, fuel pressure & delivery rate low, clogged fuel filter, dirty air filter, are some of the things that come to mind.

On spark knock, intake air tube plumbing disconnected, or rerouted, modified, or otherwise messed with, that allows hot air to be ingested by the engine, carbon build up in the cylinders causing hot spots & or increased compression, wrong spark plug heat range, cooling system dirty & not doing it's thing, poor quality fuel thats below spec for octane rating, ignition timing off, lugging/not down shifting a straight drive tranny on a pull, dirty fuel injectors giving a lean shot of fuel or poor fuel plume pattern, dirty stuck open PCV valve = uncalculated for vacuum leak & lean mixture, leaking intake manafold gaskets, leaking vacuum lines & the list goes on & on, but you get the idea, many things can figure in, so don't get focused on just one thing.

Ford cautions against using premium fuel for extended periods, as our engines compression, spark & valve timing aren't designed for premium fuel, so it won't burn completely before the exaust valve opens. It can actually cause deposits over time, that'll cause the problem to worsen. The unburned fuel also causes down stream problems like the exhaust valve & manafold running hotter than designed for & the cat converter has to eat all that unburned fuel, so it too runs hotter.

Using a tank of premium for a trouble shoot, to see if increased octane will improve a spark knock problem, isn't likely to cause mischief, but it won't cure the root problem, if it's combustion chamber deposits.

If you think the fuel injectors, intake valves or combustion chambers are dirty, consider trying 20 oz of Chevrons Techron Concentrate Plus to the tank at the pump, before filling up with Chevron, Texaco, or CalTex gas, which already have some Techron in them, this will raise the treat rate 10X above pump gas alone & will usually tidy things up in one tank. Run most of the treated tank out with daily high rpm runs at or above 3600 for a mile or two & see how it goes.

A bunch of thoughts for consideration, let us know how it goes.

 

Thanks,
Can I get this at most auto parts stores?

 

What about doing a seafoam treatment? half through the gas tank and the other half sucked into the crankcase. That would help get rid of deposits.

 

I am not familiar with that. How does that work?

 

Yes, most autoparts stores, Wal Mart, ect, carry Techron & Advance Auto has a buy one/get one deal on the 20oz size this month.

 

Finally, figured it out a couple of weeks ago. One morning when it was still dark, I looked at the engine while it was running. Sure enough the plug wires were giving me a light show. I replaced the plugs and wires and it runs great now.
Thanks for everyone's suggestions.

 

Good find fix & feedback Were the 50K wires OEM, or aftermarket???

 

The 50K wires were after market. O'reilly's refunded me for them even though they were 5 years old. I upgraded to a better brand this time.

 

OEM is good for sure, hope the new ones turn out ok over time, as our waste spark ignition system works our plugs & wires Twice as hard, so they need to be designed to take the extra work load.