1997 jeep Cherokee 4.0 and its jerking when i floor it at 70 mph or above. it will accelerate fine if i slowly accelerate past 70 but not if its floored. any ideas what my problem could be? thanks

i replaced ignition coil the button under the the cap i forget what its called rotary button or something the ignition module the plugs and wires the spark plugs. i cleaned the throttle body and tps and it still does it. the rpm needle will jump all the way to the red zone like its tacking out when i floor it after it reaches 70 mph. and i have had a mechanic check the fuel pressure.

 

mine started to rattle around 65. i tightened up the suspension and its fine now

 

its the engine jerking it want accelerate past 70 mph if i have it floored but if i slowly accelerate it will go over 100 mph with no problem

 

Sounds like a bad misfire issue. I would start by checking the plugs/cap/rotor/wires and also fuel pressure under load. Easiest way for the fuel pressure under load would be hook the gauge up and then tape it to the windshield where you can see and read it while the problem is happening.

 

When was the last time you did a tune up?

 

Here is the pressure specs

 

Kinda makes me think tps, may have problems registering property at wot. You should check all sensors with a volt meter

 

Normally the tps well not cause this kind of problem, it will cause it to cut out completely if it goes open or sorted and stall the engine

 

May want to find a different vehicle, right tool for the job and what not.

 

i replaced ignition coil the button under the the cap i forget what its called rotary button or something the ignition module the plugs and wires the spark plugs. i cleaned the throttle body and tps and it still does it. the rpm needle will jump all the way to the red zone like its tacking out when i floor it after it reaches 70 mph.

 

Again, I would check that fuel pressure the pump may be cutting out/just not able to keep up under that load. Also is that any check engine light on? If so you need to get the codes read. And let us know what they are. There is a possibility that this could be a transmission issue also. Check the fluid level hot at idle in neutral.

 

yea i got a mechanic to check the fuel pressure and i have checked transmission fluid and there all good and no cel or codes.

 

Did he check the pressure while it was in the highway doing the problem that your having

 

I had that same problem i had and it was my fuel pump what was happening was when i got passed 65 the pump would heat up and cut out like it had no power and i would let off the gas and it would slowly gain speed