are we even sure that its a Misfire....we dont know the code....

was the Check Engine Light Flashing??? because that is a Random/Multiple misfire

That is technically a catalyst damaging condition with the light flashing. There is another code for random/multiple that will set a light but not flash it. (Yes..last weekend...lol)

I only use premium fuel.

Using injector cleaner has definitely helped. The problem appear less often.

The check engine light comes on sometimes. It is not flashing. There does not appear to be a pattern. It seems random. Usually it will go out again some time later, usually after the car has been left (turned off) for some time.

I have recently replaced the plugs and the wires. This was an attempt to fix the check engine light problem.

I replaced the fuel filter.

I will try to get the codes.

Fault codes are P0135 and P1406.

Replaced front oxygen sensor, egr valve/gasket, reprogrammed pcm calibrations.

Engine light still comes on occasionally....

P0135 is Front O2 sensor heating issue.

P1406 I can't find.

What is the current check engine light from? If it'* the same codes (assumed) then you should check the wiring, and especially ensure none of your plug wires are touching the O2 sensor wires.

I checked and couldn't find anything on P1406, either. I don't believe that to be a proper code.

P01406 for a '97 is EGR position sensor performance (from Techinfo)

Maybe the same for '96?

Called garage, P1406 is the EGR.

I suppose the check engine light may be a new problem, will cost me $95 to find out.

Is there another (cheaper) way to get the codes?

How do you look up the codes, are they online?

Many auto parts stores will read the codes for you (hoping to sell you the affected part) or rent (for free) use of a code reader. You can buy a simple code reader for OBDII many places for about $30-40. Check out Techinfo section here on Bonneville Club under electrical/computer for code listings.

Here are some for sale at Harbor Freight. Note these only read codes. These are not scan tools.

http://search.harborfreight.com/cpis...ader&Submit=Go

http://www.harborfreight.com/cpi/cta...emnumber=95210
looks to be a choice for a 96.

You mentioned scan tools. What are they? Are they worth the cost? Sounds like a tool that scans all systems and diagnoses problems