Fsdegoeijen

Hi so my 2000 Cherokee sport seems to have developed a problem where it starts to shake (once warmed up) when I put it in reverse. My engine light has come on and off several times, and my mechanic tells me it is the fuel injectors. I wanted to check first if anyone else is experiencing a similar problem. And once again it only does this in reverse, once back in drive or park (even neutral) the car appears to be running fine again.
I am new to the forums so hopefully it is ok for me to post this like this.

Thank you!!

OttawaXJ

Torque? Mine shakes something fierce in reverse and feels twice as strong. Obviously due to the ridiculous gearing for the standards.

Fsdegoeijen

It's not that because it revs very irregularly when this happens and it has trouble backing up then. The smell it creates leads me to believe its something more serious than that.

OttawaXJ

eeep. Thats not good. I'm not sure what it could be

Fsdegoeijen

Computer said it was fuel injectors. Anyone know if cleaning them out could help this?

Zack92MJ

I cleaned my stock ones and put them back in (with the old orings and everything) and it was a lot better. I just sprayed the tips of them with throttle body cleaner, and whipped them with a rag.

Also I did the IAC / throttle body cleaner, found here:
https://www.cherokeeforum.com/f30/how...le-body-76947/

Pretty straight forward took me like 30 mins to do. I took off the whole throttle body, and then the IAC. Made it SOOOOO much easier.
I got a can of throttle body cleaner at autozone for like 4 bucks. Mine idles a little bitter now actually I'll post some pictures if you guys want them.

Edit: mine also 'thumps' in reverse some times too..kinda worrisome. haha

Gee oh Dee

I doubt its injectors if this only happens in reverse.

Moving to OEM tech.

Cherryokee

Does it shake in reverse when your foot is on the brake or when throttled and rolling?

Your description makes me think there's a broken motor or trans mount.

Fsdegoeijen

Only when foot is on the brake

crystalion

X2-- The couple of times my cars would shake and rattle in reverse-- "Rolling under power" I was either a trans mount or motor mount.

U seem to be saying after u start her up she runs fine or good enough then with the foot on the brake u put her in reverse she sputters and gets a little jumpy under the hood.

Which one is it ?

Fsdegoeijen

Yeah basically it runs fine. Until the engine is warmed up and I put my foot on the brake and put it in reverse, and don't accelerate in reverse. Same if I start it up with a warmed up engine, and put it in reverse to back up, it starts shaking and idling irregularly, until I accelerate a bit out of it. As soon as I put it back in drive it stays unless I bring the revs up, in that case the problem doesn't return when it is in drive. So it lies with it being in reverse

Cherryokee

Keep it simple. Start by cleaning the throttle body and Idle Air Control valve (IAC) - a cheap and easy way to step into diagnosing stuff like this. It's also time to start thinking about fuel system service/cleaning and a new Throttle Position Sensor (TPS). Do you use good quality fuel or whatever is cheapest? What about fuel system additives?

Fsdegoeijen

Yeah so it ended up being a wire In the electrical wire box, it had a little knick in it, and because of that it was sending distorted signals to the 5 and 6 fuel injectors causing it to heavily misfire. My mechanic said that he'd rarely ever seen like this and that proved itself as it took days to find this issue. At least it's solved now

Gee oh Dee

Why would they only misfire when your in reverse? That makes no sense...

Fsdegoeijen

It was misfiring in drive too but in reverse it appeared to be heavier. It later started doing the same in drive too