1999 TC Sig misses while climbing hills ?

[weedbeetle]

I replaced the spark plugs yesterday and some of the power came back but today it all went to crap again . This car sat for about 4 years before we got it last week and I have ran a tank and a half of fuel through it so far . I know it probably had some old fuel in it when we got but I have no idea how much ..... the guy that gave us the car stopped on his way here and filled it up . Am I looking at getting a new set of injectors or should I try and SeaFoam it first ? The engine is 4.6 with 94,000 on the clock and has been serviced religiously by it's previous owner ....... it was his late wife's car and has sat parked since she past away about 4 years ago .

[All2kool]

Originally Posted by weedbeetle

I replaced the spark plugs yesterday and some of the power came back but today it all went to crap again . This car sat for about 4 years before we got it last week and I have ran a tank and a half of fuel through it so far . I know it probably had some old fuel in it when we got but I have no idea how much ..... the guy that gave us the car stopped on his way here and filled it up . Am I looking at getting a new set of injectors or should I try and SeaFoam it first ? The engine is 4.6 with 94,000 on the clock and has been serviced religiously by it's previous owner ....... it was his late wife's car and has sat parked since she past away about 4 years ago .

Check every COP for rust. I had this same symptom on my '96 Cartier and it turned out to be a rusted Plug Wire.

[weedbeetle]

Thanks for the reply ..... when I changed the plugs the other day I did check all the COPs for any weird issues . They did have a greasy substance on them which I'm guessing was some of dielectric grease to ward off moisture . When I changed the plugs out I did the normal routine of blowing out the holes before pulling the plugs to keep crap from falling into the cylinders ....... any way the hesitation and stumbling was happening before the plug change . Like I said the car had been sitting for about 4 years so I'm guessing the fuel was bad . I would have drained the old fuel before even running the car but the guy that gave us the car drove it to our house and I never got the chance . I'm on my second tank of gas and one set of plugs and the stumbling and hesitation is getting worse on hills and at about 45-55 . Yesterday we went for 50 mile drive and at first it was running great ...... till the first good hill then it all went to crap until we got on the freeway ...... then it went back to running pretty good . Then on the next good hill it went to crap again and has stayed that way. Today if I get the chance I'm going to try some Sea Foam in the tank and see what happens ........ then I guess a set of new fuel injectors and plugs ?

[All2kool]

Originally Posted by weedbeetle

Thanks for the reply ..... when I changed the plugs the other day I did check all the COPs for any weird issues . They did have a greasy substance on them which I'm guessing was some of dielectric grease to ward off moisture . When I changed the plugs out I did the normal routine of blowing out the holes before pulling the plugs to keep crap from falling into the cylinders ....... any way the hesitation and stumbling was happening before the plug change . Like I said the car had been sitting for about 4 years so I'm guessing the fuel was bad . I would have drained the old fuel before even running the car but the guy that gave us the car drove it to our house and I never got the chance . I'm on my second tank of gas and one set of plugs and the stumbling and hesitation is getting worse on hills and at about 45-55 . Yesterday we went for 50 mile drive and at first it was running great ...... till the first good hill then it all went to crap until we got on the freeway ...... then it went back to running pretty good . Then on the next good hill it went to crap again and has stayed that way. Today if I get the chance I'm going to try some Sea Foam in the tank and see what happens ........ then I guess a set of new fuel injectors and plugs ?

I didn't see anywhere that you indicated a new Air Filter was installed. I'd also suggest cleaning the MAF with good MAF Cleaner. I'd also look at cleaning the EGR. I have found that Sea Foam can indeed clean dirty injectors so it's a good investment IMHO. Many will say it is nothing more than snake oil in a can.

[weedbeetle]

The air cleaner is a cleanable K&N and it is clean as whistle . I use Sea Foam in all my outboards when I store them for the winter and trust the stuff ...... it has never let me down . I just never gave it a second thought to use it in car. I know when I fog my outboards it cleans the carbs perfectly and cleans out the lower end of the block as well so why wouldn't it work in a car . I'll clean out the EGR as well.

[weedbeetle]

OBD2 says code po303 and po171 ..... now what? I changed out the plugs and still have an issue ..... in fact it is getting worse ! Which cylinder is #3 ? Is the 171 code due to the mis fire on #3 ?

[jerryg2112]

You can try swapping the coil overs from cylinder 3 and another cylinder, clear the codes, and see if the misfire code moves to the other cylinder. I did this on my 1999 4.6L continental. I had the misfire code on cylinder 1, then it moved to cylinder 2 after the coil swap. Put a new coil on and the car was fixed. If the code doesn't move you can rule out the coil.

[All2kool]

Originally Posted by jerryg2112

You can try swapping the coil overs from cylinder 3 and another cylinder, clear the codes, and see if the misfire code moves to the other cylinder. I did this on my 1999 4.6L continental. I had the misfire code on cylinder 1, then it moved to cylinder 2 after the coil swap. Put a new coil on and the car was fixed. If the code doesn't move you can rule out the coil.

This is spot on advice. It's how I determined I had a bad Plug Wire.

[weedbeetle]

So it seems you were correct ...... I ran an OBD2 on her yesterday and it showed a number 3 misfire and bank 1 rich . So I popped the hood and wiggled the COP a bit and took it for a drive and it runs like new again ? I'm guessing a bad contact at the plug ? Not sure if I should get COP just in case or just run it as is . I can't believe that one cylinder acting up would cause it to run so bad but I guess computer cars are finicky beasts . Thanks for the help so far guys .

[jerryg2112]

Mine ran so bad I couldn't get down the street. Glad you found the problem.