Ronstang

This car has been sitting since Feb 09 because of this issue. One morning it would not start when I was leaving for work and it turned out to be the starter. The car has ~130K miles on it. Since I fixed the starter the car does not run properly. It has had a rough idle/misfire since I put it back together. The engine just shakes like 1 or 2 spark plugs are disconnected....even though that is not the problem. The car also stuttered and bucked at constant speed when driving. I will list all the things I have done to try and correct this problem to simplify this post. I really need to get this car running as we are down to one car and cannot afford a replacement at the moment.

The one constant in this scenario is the problem. It has stayed the same no matter what I have done/replaced so it is unlikely that the repairs I did along the way are at issue.

- Many of the wiring plugs on the injectors broke taking the car apart so I had to order new ones and replace them all. They were soldered and I used heat shrink and seal on all wires. I have verified that all are wired correctly and all are firing with full voltage at the proper time so I have ruled out my wiring job as the source of my problem.

- One of the first problems I identified was the injector seals were bad and no longer sealed after the initial tear down. Some were leaking rather badly so I assumed that was my problem. I ordered new seals and got new pintle caps for the injectors. After taking the intake manifold off a second time and installing the seals the problem remained.

- At this stage I moved on to the spark plugs/wires/caps/rotors. I could not verify the original equipment was functioning properly and some of the wires were out of spec with too much resistance. I decided to do the timing belt at the same time replacing the water pump and all the idler pulleys at the same time. I also did the valve cover gaskets since they were leaking and I thought that could be contributing to the rough idle as the plugs and wire ends were in a pool of oil....this issue cause a rough idle on my 93 Taurus SHO. The plugs were changed and all new wires and caps and rotors were changed. I used the good stuff, not the cheap junk. The problem still remained. I triple checked and the timing belt is definitely installed correctly.

- I then determined that I somehow had a vacuum leak. That explained the stuttering and bucking at constant speed so I figured I somehow messed up installing the intake. The perplexing part was how I did it twice. Turned out these cars have junk for intake manifolds and they tend to warp when you take them apart. I found the spec for out of tolerance in one of the books at the Lexus dealer. The intake halves did not sit flat with each other either. Luckily I have access to a machine shop so I used a fly cutter and slightly milled the mating surfaces of both halves of the intake. Upon putting the car back together it still had a rough idle but the stuttering and bucking was now gone. At least one of the problems has been solved.

- I have verified that all the injectors are working correctly. I had them tested on a flow bench and all are the same with a nice pattern.

- I borrowed a new coil from my buddy who has a repair shop and I tried it on both sides and the problem persists so neither coil is bad.

- I blocked off the EGR system since they can create a vacuum leak. The problem persists.

It seems to be an electrical issue but I cannot locate it. I have two ignition modules sitting on my work bench which I got out of a car at the junk yard. I figured I would trade them out to see if that might be the issue but I wonder how that could be the problem after simply replacing the starter.

I am baffled here and could really use some insight. Is there a possibility something is wrong with the cam or crank position sensors? If so is there a testing procedure? Could disturbing the wiring harness that have caused an issue I am missing? Any help would be greatly appreciated as I really need to get this car back on the road.

Thanks,

Ron

tonyfazt

check the fuel regulator (drum looking thing on the left ) where the fuel line meets
and also check that the rotors are in the right place

deanshark

x2. when you put the new rotors on maybe you put them 180* off. When you did the timing belt did you also change the tensioner or just the idler pulleys?

Ronstang

Thanks for the reply guys. I am very confident that the rotors are in the correct location as I triple checked everything. This issue was present before I put on the new rotors and after, nothing changed. It has run rough, in exactly the same manner, since I put the car back together after I replaced the starter. The only improvement being I fixed the vacuum leak left by the warped intake manifold. It no longer stutters or bucks at speed but it still runs rough. It seems to be a misfire and thus electrical. Although I cannot really tell. When you start it you can feel the engine shake a little and it is really noticeable when you put it in gear. You can also hear it in the exhaust. There is a distinct choppiness coming from the tailpipes.

I have also changed the fuel filter. I also put all new idler pulleys and the tensioner when I did the timing belt. I ordered a kit. Like I said in the OP this issue has remained no matter what repairs I have have done. I did not solve it nor did I make it worse. It is an annoying gremlin. I guess I need to get out there today and change the ignition modules out with the ones from the junk yard so I can eliminate that. It would be really nice if that was the problem.

Thanks

nervekiler

same symptoms as my car that started when the starter was replaced.

my car DOES throw a check engine light once in a blue while... about once a week and then itll turn off for a while. i identified the light as reading the TPS malfunction and also saying the car runs lean.

i wonder how i can tell if my intake manifold is also out of spec? should i spray ether or starter fluid around the intake to see if it changes the idle?

im hesitant to bring the car back to the shop that did it a year ago because i originally had to bring it back when i first got it from them because of a fuel leak out of the rail which they then charged me to fix! i dont trust mechanics because, as far as im concerned, anyone can call themselves a mechnic.

Ronstang

As far as telling if your intake halves might have a leak I just put the halves together without gaskets and could feel them rock back and forth. They were obviously not level. I milled mine and after I did the the major bucking and stuttering went away and it stopped throwing codes.

My car now just has a rough idle that you can hear in the exhaust and it shakes a bit, especially in gear. It revs up quick but it is a little "poppy" or "raspy" so I might have a vacuum leak somewhere else. I just don't know where to look. I even bypassed and blocked off the EGR so that could not be a vacuum leak....no different.

mebush

check the wires leading to the throttle position sensor and also the pins on the sensor itself. Had the same problem after starter replacement and my problems were in this area.

Ronstang

What exactly am I looking for? The connector itself broke when taking it off. The little clip thing that holds it on is all that broke so I just now zip tie it in place once seated.

mebush

Broken / loose wire, loose pin, etc. If nothing else try just jiggling it around with the motor running---it may die or it may smooth out. That's what mine would do. I ended up replacing the sensor to fix it.