Recently, My L98 has has a surge at idle. It sounds like the car revs, just starts to putter out, and then revs again. It's very annoying.

What could this be? I know it could be a spark plug, a wire, the idle control valve, etc. What is my best bet for replacement so I don't spend an arm and a leg hunting down a gremlin?

Also, I have smoke on start up. I know this is probably a valve seal leak. All the shops want over $1,000 to fix it, so I'd like to tackle it myself. Does anyone have instructions on how to do so? What tools are required?

Thanks for the help!

Bill

 

#1 cause of a surging idle, bad EGR valve. Valve seals easy but time consuming. The only real tool you need is a decent valve spring compressor and something to hold the valves in place either a air hold fitting or a nylon rope. As far as doing it is concerned if it was a short process ide just type it out but being that its so long start to finish ide really recommend just looking up the process either on autozones web site (free) or picking up a repair manual. Basically all it is, is holding the valve in place with compressed air or filling the cylinder with nylon rope through the spark plug hole, compress the valve spring, remove the keepers retainer and spring, instal the seal and re assemble.

 

Plenty of threads on the valve seal job, and it can be done in the car without taking heads off - do a Might even be a stickie or tech article on it.

$1000 is a total rip off - a whole BRAND NEW set of high performance heads can be had for that! Valve job should be no more than $300, and that should include 3 angles, new Viton seals, and machining any surface issues! Are you talking to some garage, or to a machine shop? Are you getting quoted with you taking off the heads, or them? For $1000, I'll fly to TX and do it myself!

Check for vacuum leaks on the idle surging issue.

 

Gentlemen,

Thanks for your help! How do you check for vaccum leaks, and how much is an EGR to replace? Is the install easy?

Thanks again,
Bill

 

Vacuum leaks are best found by spraying something like propane gas over any area that could have a vacuum leak. If you spray an area and the RPM changes you likely have a leak there. As far as the EGR valve is concerned, Its not terrible just time consumeing. The EGR valve as isnt too bad expense wise either I seem to remember buying one for roughly $30? Unfortunately the EGR valve lies in the middle of your TPI intake on top of the TPI base. This means to replace it you must remove at least the plenum and probably easiest to unbolt the runners too. From there its 2 bolts and a vacuum line.

 

Valve stem seal replacement is easy. Just bring the piston in the cylinder you are working on to top dead center.(both valves closed,piston at the very top of its travel.). Then if you have access to compressed air, take out the spark plug and thread in the air hold fitting and connect up the air line. This is after you have removed the valve covers, loosened the rocker arms and swivel them to the side etc. Install your valve spring compressor on the valve you're working on, compress the spring, remove the keepers on top of the valve stem, remove spring. The seal is now directly accessible. Reassembly is in reverse order of above steps. To use the nylon rope trick, again you bring the piston to TDC, then making sure you have enough rope begin threading it through the spark plug hole until it fills the cylinder and you cant fit any more in. Make sure you leave a long enough piece hanging outside the hole so you can remove it when you are done. Then just move on to the next cylinder until you are done. See your manual for valve lash adjustment. It is vital that the valve lash is correct. You could probably get the whole job done on one Saturday in your driveway.

 

And I don't know about the TPI cars, but there were two different EGR valves on alot of the TBI and carb cars - so remove the old one and take it with you to get it replaced, so that you can identify whether it is a negative or positive valve.