00' GC won't accelerate

[bauer012]

I have a 2000 GC Laredo 6 cylinder 4.0L. About a month ago my jeep was over heating and eventually had the head gasket replaced.

After this occurred it drove smooth with no problems for about a week, until the engine/tranny light began to blink (the light has been on for quite a while from an oxygen sensor that i have not had replaced). The car began to shake while idling and was very sluggish when accelerating from stop (I've gone so far as putting the pedal to the floor and it stilll is bogged down).

I went back to the mechanic and they replaced my spark plugs and associated wires. It was driving fine and everything seemed back to normal (engine/tranny light still on but not flashing), but a week later the light came back on and the same problems resumed.

Anybody have similar problems or possible solutions?

[bauer012]

I forgot to mention that these problems only occur after 10-20 minutes of driving. Also, I'm getting some vibration in the steering wheel and gas pedal when I get over 55 mph.

[fredjacksonsan]

First, I'd replace the sensor that is causing the engine light to come on.

Next, are you getting any trouble codes?

[fredjacksonsan]

Also, the 2000 model year had a potential problem with the head cracking, do a search in the Cherokee under "0331" and you'll find threads and good information about it.

Basically, it's hairline cracks that allow coolant to get in your oil, which in time will ruin the engine. The solution is to replace the head with a pre-99 version. The cracks aren't usually visible and don't start to leak until the engine heats up....which I'm thinking is going along with your problem starting about 10 minutes after startup.

[dornier34]

Originally Posted by bauer012

I have a 2000 GC Laredo 6 cylinder 4.0L. About a month ago my jeep was over heating and eventually had the head gasket replaced.

After this occurred it drove smooth with no problems for about a week, until the engine/tranny light began to blink (the light has been on for quite a while from an oxygen sensor that i have not had replaced). The car began to shake while idling and was very sluggish when accelerating from stop (I've gone so far as putting the pedal to the floor and it stilll is bogged down).

I went back to the mechanic and they replaced my spark plugs and associated wires. It was driving fine and everything seemed back to normal (engine/tranny light still on but not flashing), but a week later the light came back on and the same problems resumed.

Anybody have similar problems or possible solutions?

what code you have ?

[dornier34]

Originally Posted by bauer012

I forgot to mention that these problems only occur after 10-20 minutes of driving. Also, I'm getting some vibration in the steering wheel and gas pedal when I get over 55 mph.

the vibration is caused for the wheel balance , what code number you have right now ?

[bauer012]

I'm not exactly sure if the replacement head was pre-'99 or not, but they checked for cracks and said it the original was warped.

Also, on the diagnostic codes they pulled indicated trouble with the transmission, but it wasn't something they could really give me a conclusive answer on what was wrong....basically they had no clue.

Thanks for the input guys. Fred, if coolant is seeping into the oil what would be the proper fix to this? Oil change/engine flush or something more drastic?

[fredjacksonsan]

If they replaced the original head with a 99 or 00, then you might get the same issue after x thousand miles. It's a cracking of the head then failure of the head gasket...replacing the gasket, from what I've read, buys you some time.

IF you're still getting coolant in your oil, you should change it frequently, say every 2000 miles, until you get the head replaced. But with the replacement head the problem may have gone away...I would call the shop, and find out what year the head came off of...if they don't know, find out what junkyard they used and call them; hopefully they'll have the records of where it came from.

A place to get your oil analyzed is Blackstone Labs; I've used them in the past and they found the coolant in my '00's oil. It costs about $30 to have it analyzed, but can be invaluable.

[dornier34]

if you see the coolant mix with oil into the oil pan means your head gasked is not good ,or someone installed the head gasket in the wrong position IS YOUR JEEP have overheating? like Fred said make sure your engine has the right head gasket, if was you I take the engine out and replace the head gasket with the right part number from the dealer