AzPete

Ok....the 02 Vert auto has about 99,000 miles on it. I do not know the history since I have owned it for 2 months/2500 miles. Ran great until the last couple weeks or so.

Started surging at steady speeds and idling. No specific speed or rpm. It seems like more of a drop of rpm vs a real surge. WOT is fantastic....no surging...downshifting to slow using the engine gives no surging. Tranny shifts fine both manually and auto.

Has CAI with stock MAF and no tune. Has flowmasters and the rest is stock exhaust.

NO CHECK ENGINE LIGHTS of any kind. Brakes work smooth and freely with no dragging. MPG is 16+ all the time with no smoke from exhaust.

Cleaned the IAC with very little change in the cars running. Tried both 93 and 87 octane gas with no difference. Tried three different brands of gas plus a bottle of injector cleaner. May have had a bit of difference with the cleaner running thru but not real noticeable. No vacuum leak found with normal tests.

Dealer had it for 2+ days with no problems found running every test they could. There was a time that one injector showed bad but cleared itself. Fuel filter looks old but if it was clogged, WOT should be effected drastically. Filter will be changed and plugs looked at on the return to the dealer on Monday. Yes, I could but I don't want to change it in the rain.

Any ideas..........

school boy

Vaccum leak?

AzPete

All vacuum seems good....no leaks found using the normal spay of the hoses and watch for rpm increase.

I am leaning towards plugs or injectors even though the testing does not indicate them....

At times, it runs smooth, and just as I think it might be cleaning up....it stumbles again. Feels just like when you drive a car thru water on the road when at speed....just a drag for a couple of seconds, then fine...plus it does it at idle......

Shampue

Regarding your IAC, sometimes cleaning it won't work. It is an electronic component after all. Sadly, the IAC for the 02 model is like $85 compared to the 99-early 01 which is only $50-ish.

AzPete

Does the IAC have any control at cruising speeds....always thought it was out of the equation at cruising speeds.

Shampue

Not at cruising speed.

AzPete

So....they pulled a plug this am....it has copper plugs which should be platinum plus the gap was around .35 when it should be around .50. Those will be replaced and a new fuel filter installed and the mechanic feels it should fix the issue....

Dang previous owners.....hope this fixes it.

dawson1112

I think the mechanic is just guessing.

While this surging is going on do you have the A/C running?

If the refrigerant gets a little low, or the pressure sensor on the line start to go bad it will cycle your compressor clutch on and off, this will seem like the engine is surging at idle and while cruising.

AzPete

A/C on or off, no difference. In or out of gear, no difference.

Yes, they are guessing since no type of test reveals any issues. The plugs are definitely wrong....no doubt once I saw them. Different length and type as a minimum.

One injector is at the high end of the test limits meaning it would be lean if any indication showed on the computer....but no results indicate poor fuel ratio.

AzPete

So....it is home and running great. From when we purchased the car, I planned on doing the fuel filter and had it planned for this next weekend....now Ford did it and the old one was extremely dirty.

Also, the plugs are new now. The there were two different brands and three different numbers. One was a short plug.... They all looked bad....dirty, some with burnt electrodes and different gaps on all. Looked like the original plugs and fuel filter.

Would not normally have Ford do this stuff but wife has surgery this week, family visited last weekend and sister will be in to help while wife is down. Sister needs a car so I had to get it done quick.