97 ford f150 4.6 4x4 running rough?

Ok im going to try and make this clear as possible. I just bought a 97 f150 4.6 triton 4x4. I ran and test drove it for atleast an hour had no problems except codes for egr and an o2 sensor. I drove it 88 miles with no problems what so ever. The next day i got in it drove probably 5 miles and heat went to cold, and was pouring coolant out of tank. but did not overheat. gauge stayed a norm op. I pulled over shut the truck off took cap off and let set for about 10 minutes. cleared the 2 codes got in started fine and drove for about another 5-6 miles no problems at all, heat was hot. parked it got ready for work got in it and drove about 3 miles and heat went cold, again temp gauge read good, and this time it wasnt pouring coolant out( which after the first time i filled back up) but there was pressure on the cap. so I shut it off let it sit for about 10 minutes got in took off for work heat was warm still not overheating. made it to work fine. I put a new cap on and tested the old one and it wouldnt hold pressure at all. I leave work about 2 in the am and drive about 5 miles and temp gauge pegs out for about 5 seconds then back to norm op range. but check engine light was flashing and started running rough. so i pulled over to get gas anyways and i took the cap off and let in sit. put cap on started temp gauge was in norm op range, but still running rough and a lifter tapping. I nursed it home and parked it. got up today to flush coolant system and change thermostat and each time ran it atleast 30-40 minutes never over heated didnt pour coolant out but still running rough and lift tapping. I checked oil it was about a quart low so I added a quart and some stp oil treatment and continued to flush system. still rough running unless you get into the throttle pretty good then it runs fine until you idle but never tried dying, still lifter tapping. any Ideas where to start? i think i know what most will say and what someone will know exactly but im hoping there might be something else wrong with it. and how do i fix the lifter tapping?


it was a private seller, told him about it and he said he never had the problem and drove it daily, so thats a dead end and i dont have the money to fix the truck and take him to court and wait. just wondering if anyone had any ideas on what could be wrong, how to fix or whats it worth like it is.

Update 2:

i didnt get to pull the codes when it was flashing. seeing as how i have noone but me and my kids i had to get it home by driving and im close to broke. but it flashed that time and then went solid when i oulled over, i dont remember if it flashed anymore on the way home, but today like i said i flushed alot of the old coolant out and it wasnt flashing just solid. so i pulled the battery cables( and i know this is a temp fix) but it went out. after about the second flush and adding oil i took it down the road maybe 1/4 mile and the light never came on. nor did it come on the whole time during the flushing process. but the two codes i puled off and cleared after the first time it blew coolant out were the egr valve and an o2 sensor.

3 Answers

  • 7 years ago
    Favorite Answer

    What codes did it throw when the engine light was flashing? That's where I would start. If you ran the engine after the check engine light was flashing then you might've done serious damage. When the check engine light is flashing that means a potentially catastrophic problem is happening at that very moment, and you need to pull over and shut the engine off right then and there. When the engine light is just on but not flashing, it means that there was a malfunction ( could be something minor) but the malfunction isn't immediately critical.

    Edit: Gets the codes read. The fault codes should still be in the KAM.

  • g-man
    Lv 7
    7 years ago

    From your account it sounds a though you may have solved the overheating and lack of heat issue with the system flush. You didn't tell us the mileage on the truck or where you live as it could have a bearing on that possible lifter noise. There's a good chance the lifter noise is just that but if it is, I can tell you the engine can run a long time with a noisy lifter. Another possibility, if you live in a colder climate where salt use is common in the winter, is a small exhaust leak in one of the manifolds. When they first start the sound is similar to a sticking lifter, a rhythmic ticking. To set your mind at ease, the engine being a quart low on oil should have no bearing on either the noise or the overheating.

  • 7 years ago

    when person sells truck or car as is they need tell all things wrong with it etc.. this sounds like a problem the owner or dealership new about and if not disclose you should get your money back. or try in court to do so. sounds like a valve problem or worse. I personally try get my money back.

Still have questions? Get your answers by asking now.