So after i start my car my engine pulsates Almost like power pulses. Which in turn makes my lights go dim and then normal. Idk if its a sensor thats changing air/fuel ratio quickly. New battery. Connections to alternator is good. And when its colder, when i start it, the rpm's almost drop to where it stalls out then recoups back to normal rpm's.
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Pulsation in my engine and lights
- Thread starter kevin
- Start date
DanMyers
Hard-core CEG'er
Try taking off the IAC (be sure to have a new gasket on hand) and spraying it out with some carb cleaner, if it's a problem at idle the Idle Air Control valve is probably sticking. If you have the V6 it's a good idea to take off the intake manifolds, throttle body, and EGR and clean them because they are probably completely gummed up, put in a new PCV, and if you haven't done it in a while put in new plugs, wires, and fuel filter. Last I knew gasket sets will set you back around $60 from an auto parts store, Berrymans B12 for cleaning is IIRC about ~$5 a can, should probably get 4 cans, get a set of cleaning brushes and use the ones that are stiff metal, but not sharp. Those will cost about ~$5, and the fuel filter is inexpensive, all told if you don't do plugs/wires you will probably spend around $100. Might want to check out the secondary linkage as well as you'll have to remove it for the LIM and the clips used can get very brittle and break.
That is of course if you have the V6 and feel like being comprehensive, honestly it's probably just a sticky IAC valve, but the IM cleaning is awesome and will definitely be noticeable. A tune up is always a good idea.
That is of course if you have the V6 and feel like being comprehensive, honestly it's probably just a sticky IAC valve, but the IM cleaning is awesome and will definitely be noticeable. A tune up is always a good idea.
Do the lights dim once and then come back to full brightness, or do they cycle? My Probe had a weak alternator that caused the lights to dim and then get brighter in a continuous cycle.
ilovesvt
Veteran CEG'er
Couldnt the pulsating headlights be that alternator wire isssue that tons of EO 1998s get ???
Try the battery before you try the alternator. Sometimes a battery can be so dead that it forces the alternator to work harder, causing pulsations in the lights, and guages. So a bad battery can make it look like your alternator is jacked. Then check the alternator.
I know that this is exactly what you don't want to hear, but I have the exact same problem. Car runs good at startup, then almost stalls before recovering-- at which point the pulsing begins. It isn't just the electronics, but the engine too. It pulses forward then back, like i get on the gas, then let off, then back on again. I took it in to a trusted dealer, hoping to God that it was the battery, or even the alternator.
Unfortunately, it was my harness itself. Quote? $2500 parts and labor. Problem now is, who has them. I have been seeing quotes around $1200 for the harness itself, but I am currently looking for something less expensive.
As for now, try the battery, then the alternator, then look into the harness. Let's hope it isn't the harness!
I know that this is exactly what you don't want to hear, but I have the exact same problem. Car runs good at startup, then almost stalls before recovering-- at which point the pulsing begins. It isn't just the electronics, but the engine too. It pulses forward then back, like i get on the gas, then let off, then back on again. I took it in to a trusted dealer, hoping to God that it was the battery, or even the alternator.
Unfortunately, it was my harness itself. Quote? $2500 parts and labor. Problem now is, who has them. I have been seeing quotes around $1200 for the harness itself, but I am currently looking for something less expensive.
As for now, try the battery, then the alternator, then look into the harness. Let's hope it isn't the harness!
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it's a 2000 svt btw. the battery is new. 12.6 off, and 14.4 when on, and under bunch of load it;s 13.8 or something. was seeing other problem guy had with this, they were saying voltage regulator is bad in alternator. which sucks cause i dont want to replace it. and the lights cycle. same as the engine. and the stalling is (hopefully) a dirty maf or iac or something. or maybe bad plugs
Just to throw out a different possibility altogether - could be a vacuum leak. Like stated above check your PCV valve and intake area for loose hoses etc. The pulsing lights with the engine revs is normal when the car is cool, but pulsing engine revs is an indication of a vac leak.
Redlineracer12
Addicted CEG'er
I'd look into getting the car to idle properly first. Odds are the engine speed is dropping too low causing the lights to pulsate. Fix idle, then worry about the lights dimming if they're still doing it. 
You shouldn't have the harness issue with the 2000 model year. I'd start with IAC, PCV, and and intake cleaning (with new gaskets all around) myself. If the plugs are older I'd replace them while I was in there.
You shouldn't have the harness issue with the 2000 model year. I'd start with IAC, PCV, and and intake cleaning (with new gaskets all around) myself. If the plugs are older I'd replace them while I was in there.
CSVT#49
Addicted CEG'er
Do you a check engine light on? Just curious because most vacuum leaks would cause a CEL. However there are a couple that won't (HVAC related)... the plastic vacuum lines on the back of the engine are where I would check first they are prone to crack when they get brittle. The EGR (green line) and fuel regulator, EGR solenoid (red lines), and the HVAC (gray line) are all on the back, which is what I would look at first. One indicator of the gray vacuum line being broken is if your HVAC vents do not open properly... IIRC the vents should act like you have the defrost on all the time regardless of what you have them set too. The EGR line should cause a CEL if it's cracked. If the engine is having the big of an issue idling you should be able to hear the leak too. One good way to check for a vacuum leak too is to spray carb cleaner around the vacuum lines and if you get a surge in engine rpm then you've found the leak area. Other spots to check are the breather/PVC lines that run up to the accordion intake tube. Another easy thing to do is buy some MAF cleaner and spray out the inside of the MAF. All of the above are cheap and easy things to check.