when i run my 97 4.2 (which just clicked over 100,000 miles) hard and then stop at a red light it wants to drop the rpms below 500. i just had the tranny rebuilt a lil over 10,000 miles ago and changed the tranny fulid and filter. Ive tried running higher octane gas and enough fuel injector cleaner through it to keep stp rich for a while. ive also replaced the air filter. i cant seem to figure this out. It doesnt do this when i dont let her scream.

 

When the RPMs drop like this, it's usually the IAC (idle air control valve). If it were a vacuum leak or misfire, your check engine light would probably be on. You can remove the IAC and try to clean it. I like Brakeleen (in the red can) for cleaning parts like this.

If it's not the IAC, then look for vacuum leaks.

By the way: How's your coolant level? Has it dropped any?

 

My coolant level hasnt dropped very much since i had the timing cover gasket replaced. i guess ive lost about a quarter of cup since june 03 when it was replaced but not as much as i was before the faulty timing cover gasket was replaced.

do yall think it could be my fuel filter?

 

Howdy Bearcat,

I have the same problem when I run my A/C. I t runs really rough! I just rev it up alittle and it clears up. Mine is a 5-speed.

If u didn't change ur intake gasket u might want to do that too.

Paul

 

how much does it cost to replace the lower intake gasket? it happened again tonite , i turned into my driveway which is staight up and stopped to talk to my brother who was outside and it dropped again soo i put in neutrel and revved it up and it cleared but this is really beginning to worry me could a faulty intake gasket lead to bigger problems if it doesnt get fixed immediatly?????

 

Howdy Bearcat,

The gasket will run 'bot 90 bucks. Don't start ur engine again until u get it fixed. This is the #1 cause of engine failure in the 4.2 V-6. It happened to me.

Paul

I got mine back on the road!

 

stengun, ive heard of another97 V6 f-150 in my area that started his truck one mornin and bent the rod in one of the cylinders i belive it was cuz of coolant build-up in that cylinder and when it crunk soo much pressure built up in bent the rod. How true do u think this and could it likely happen to me?

 

bearcat,

Read the Website: www.leakingfords.com I created it because there is no way I could post all of that information over and over again in message forums. It will explain what the problems are and exactly what happens when the gaskets fail and coolant leaks into the cylinders.

Bent and broken rods are very common when the lower intake gaskets fail. The majority of people that email me through the site say they found it while searching the internet for a 4.2L replacement engine. Since Ford took care of many of the faulty front cover gaskets with the 99B29 program, most engines are now failing from the faulty lower intake gaskets.

If your coolant level has dropped at all since the front cover gasket was replaced, you should be concerned that the lower intake is also leaking now. The gasket kit is not too costly. But, you will need to pay for around 6 hours labor if you can't replace them yourself. Average cost is around $450.00 parts & labor to replace the lower intake gaskets.

 

Howdy Bearcat,

That is exactly what happened to me. I thought that the starter was stuck, so I rolled the engine backward alittle, the tried to start it. Thats when it bent the rod. I drove it for 36,000 miles after that, but I knew it would break at anytime.

I still think the dealership owes me for a new motor.

If you are losing coolant, DO NOT START YOUR ENGINE UNTIL YOU GET THE GASKETS CHANGED.

Paul

 

Thanks for all the info, real nice site yall got going on here glad to be a member. Truck is headed to best shop in town hope itll make it there.......