Hello,

I have a 1999 Grand Cherokee 4.7 V8. I just recently started having some issues with it. I have to turn the key over twice in order to get it to crank. Sometimes it cranks fine and then others it'll idle really rough and shakes bad.

Also sometimes i can crank it put it in reverse and it will have a terrible knock and will not go over 10mph. Then sometimes when I take off it lags and i can get to about 4RPMs and it'll only go about 15mph and then it'll take off fine.

I have replaced all spark plugs, vaccum lines, upstream O2 sensor and none of those have fixed the problem. I can clear my check engine code and about 30mins later it'll come back on.

Also if i leave it idling for about 5 minutes it'll start to shake really bad and jerk when i press the accelerator. I am stumped on what else could be the issue. If anyone could help me solve this it would be great. I have until Feb 1st to get it inspected and I am in a time crunch. Anything will be appreciated!

 

My opinion? Clean the Idle Air Control and let the trans warm up a bit in neutral before moving it.