iluvmud

Hi guys, need some help.

have a 99xj that has really given me 0 major problems till now. here's the issue

-i can fire the jeep up and it fires right away(it used to take a while to fire up but has since stopped doing that)
-it idles fine and if in park/neutral when i hit the throttle it seems to run fine
-put the car in drive, give throttle it and it starts to sputter- happens when being driven

No codes are being thrown so I'm not 100% sure where to start. I'm thinking fuel pump but it was replaced a little over 2 yrs ago.

Anyone have any ideas?

Thanks in advance for the help.
MUD

freegdr

Did you check for codes or just lights not on ?

t.mcginley.jr

Sounds like a misfire/vacuum leak. There's really no codes being thrown? I feel like obd2 would pick up something.

How many miles on it?

iluvmud

the CEL works, so if one goes off it would display

yeah, so im thinking misfire, but wouldnt it be happening at idle in park/neutral too...

t.mcginley.jr

Sometimes a small misfire won't be felt in park/neutral because there's no load on the engine. As soon as you put it in drive it loads up and becomes more noticeable.

Could be something simple, when the last time you changed spark plugs? Any loose or crumbling vacuum lines? Dirty throttle body?

toasterknight

The light doesn't always come on with codes.

Jeriko

My old 92 had something similar. Would be hard to start, but as soon as it caught, it'd idle strong. Put any foot into the pedal and it'd bog and die. Replaced O2, MAP, plugs, etc. Turned out to be the idle air control valve. Just my experience.

t.mcginley.jr

He's right, any OBD2 car can have "pending" codes that won't set off the CEL but still be stored in the ECU. Get autozone or somewhere to scan it real quick, it's free.

iluvmud

didnt know that, will take it to them to check! I think this weekend i will give the plugs/wires TB a visual inspection see if i see anything.

Thanks,
MUD

gonnakill25

Do obd1's work as well?

t.mcginley.jr

Usually OBD1 will always illuminate the CEL, simply because there aren't nearly as many error codes as with OBD2. There's only about 30 OBD1 codes, so when it throws one there's probably something actually wrong. OBD2 has hundreds of codes, some more minor than others. It has to detect the same series of events a few times before it illuminates the CEL, so there can be pending codes.

iluvmud

Ok guys, so its been a long time since ive looked at this (had an intern chauffeur me to/from work) Now i need to get it fixed. I will try to run it to oriellys/autozone to check for codes, i bought new plugs cause why not. I will also pick up throttle body cleaner and clean the Map sensor, TPS and IAC....... just the whole throttle body. Also inspect cap, rotor and replace the coil(it looks pretty rusty for being less than a year old) and check the Taylor plug wires. Also, while im at the auto store, I will rent a fuel pressure gauge as well to test that, it is a new Bosch that was installed about 2 yrs ago so i hope thats not already gone out. Any other suggestions or ideas at this stage?

Thanks for all the help.
MUD

gonnakill25

I had a really bad idle problem and it turned out to be the ignition system. So I went and did the full tune of cap rotor plugs and wore and it ran great. I know it's a simple thing. But just visuals don't so alot. Just change it, cheap and good to completely rile it out.

iluvmud

So here's where I'm at now. i figured it would be best to do a seafoam cleaning via intake. after pouring about a 3rd into the intake slowly..... smoke started pouring out of the engine, it appeared to be underneath where the intake/exhaust manifold meet. Im guessing two things, cracked head, or crapped out gasket, I'm trying to see if i can get the header/intake bolts tightened but the engine is an running temp so i'll have to wait and see if any bolts have worked their way loose.

any other suggestions?

t.mcginley.jr

If smoke was pouring out from the intake/exhaust area then you definitely have a leak either at the gasket or a cracked exhaust manifold. How many miles are on the motor? See if you can pinpoint where the smoke comes out, like from where the manifolds meet the head or down further on the exhaust somewhere. I'm thinking it's the intake/exhaust gasket gone bad, or loose bolts, or both. Therefore causing a big misfire condition.