Head Rebuild - JeepForum.com
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post #1 of 2 Old 08-08-2005, 12:00 PM Thread Starter
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2005 WK 
Join Date: Jun 2005
Location: Omaha, NE
Posts: 933
Head Rebuild

Hey fellow Jeepers,

I can't figure out whats going on with my jeep. I have replaced injectors, MAP, IAC, TPS checked the crank position sensor, firing order O2 sensors fuel pressure. I still have the rough idle and the bucking and jumpin gand lunging inder load from 1500-1800 rmp. Seriously considering rebuilding the head new valves lifters rods rockers springs everything. Anybody else done this do you have any idea about the cost of parts and time frame roughly. I will not be taking it to somebody else to fix I can't afford that so will be doing it over a weekend. The jeep is a 98 sport whith a 4.0L manual..I keep getting a cylider 1 and 5 miss fire i have spark and air and a new injector. Seems to be a more internal issue as nothing is helping it. Seems to be running real lean. I have spent $300 replacing sensors that didn't need replacing and am tired of getting no where anybody got any ideas?? Goin gto save up for a couple for a couple of weeks as this isn't going to be cheap....thanks for any help or info....

OUT WITH THE OLD R.I.P. 98 TJ Sport 4" Procomp lift/adjustable lower control arms and track bar **** Cepek FCII 33x12.50x15/**** Cepek DC-1 wheels
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post #2 of 2 Old 08-14-2005, 09:50 PM
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I am unsure if what the IAC sensor is but I am guessing ignition control of some sort?

You neglected to mention the amount of miles but here's a few ideas I had.

I know you said you checked the wires so i assume you made sure its got a spark.

What about your cam sensor? If thats going out, the engine will run poorly.

When is the last time you changed your spark plugs? if they look good and are gapped correctly, then forget about them. On a side note, if they are those fancy 4 pronged platinum/gold/moondust or whatever the heck they put in those things now, they can cause problems like rough idle or poor running conditions.

Check you timing belt, it may have slipped a tooth and be a bit out of time.

Maybe you have bad fuel? Today's gas is more like H2O so you may want to invest in a bottlew of octane booster if you are running 87 octane.

As for reworking the head, as I work in a machine shop, I can give you some info in that area.

I do not understand what you hope to achive be replacing rocker arms. Rare for them to go bad. The lifters can go 'flat' and not pump up with oil causing a poor run condition. I can understand replacing valves if they are bent but don't replace them if its not needed. Once the head is off AND the cam is pulled you can check the valves to see if they are sealing by standing the head on its side with either intake or exhaust facing up and them filling them with a solvent. If the solvent runs out like a river, the valve is bent or needs refaced. It it does not seep at all or seeps very slowly, it is usually deemed usable.

As for vendors for parts, you could go to the Dodge garage and buy your parts and spend a ton of cash, or find a vendor of engine parts that are as good as OEM, I reccomend SBI engine components, they are affordable and very good quality.

I don't want to see you dump a million dollars into your Jeep but I don't think your problem is in the head. It sounds to be more electrical
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