I know I know, sounds like an ignition problem... but, I just replaced the wires and plugs not even 10,000 miles ago! It's not an all the time thing, when there's no engine load, no jerkiness, under full throttle, jerkiness (misfire or no fire?), and in slight acceleration circumstances, SOMETIMES it's there. I sprayed water on the wires tonight to see if I could see any signs of bad wires, but nothing. In park or N it doesn't happen. So what do you guys think.... Coils??? How much are those things and how do you know if they are toast or not?
Is the check engine light coming on when the car acts up? If so a code scanner would help point you in the right direction. If it's not coming on, I would say just double, or it will probably be quadruple by now, check all your work and make sure nothing is loose. Pay close attention to the intake, where it attaches to the throttle-body, and the breather hoses that come off of it to the crankcase and idle-air control. If any of these connections are loose, cracked, or not hooked up you will be drawing air past the mass-air meter, and that could case a power problem. (The car would think it's lean at the O2's and add too much fuel to compensate) I would expect idle issues if the leak were very bad, but it's worth looking into. Also, did you check the plug gap? Sounds like a stupid question, but sometimes one of the plugs can hit something going in and change the gap. Other than pulling them to make sure, the wires are the only other thing, they can be a real bear to get back on the plugs.....so double check that too. Good luck!
1993 Grand Marquis w/170,000+ miles and counting. Now it's time to make her FAST!!!
12" conical K&N filter, Custom side exit exhaust with X-pipe and Dynomax Super Turbo mufflers, replaced stock fan and clutch with PI electric fan and PSM fan controller, Aluminum PI driveshaft.
Body mods include a '95 Cobra rear spoiler, tinted windows, 17" Mustang Split 5-spoke rims w/ P255/50-17 BFG g-Froce TA radials, and a 14,000lb Auxillary Trans Cooler.
Interior: Custom A-pillar guage pod w/ Digital oil pressure and Trans. Temp. guages.
Anyways, Yup, checkede the wires, pulled the plugs, but have't checked for vac. leaks... (I figured a vac leak would grow more troublesome as engine speed increased due to greater intake vac. but when I punch it and it down shifts the problem becomes less apparent...)
Could it be a cloged or leaking fuel injector? What size are they...if they are 19lb/hr units I'll just use a set off my IROC (used to be a 305...now a 420SBC...fast is a way of life and 19lb units couldn't feed an additional 115 cubic inches :) )
Have you ever replaced the belt? My car would have a surging sensation (was not as bad as a seizure feeling) but after I replace my belt (which did not look that bad) it went away. It is an interesting feeling. It is like the tires are breaking loose or the tranny is slipping. The belt fixed my problem, your results may vary :-)
I used a Kelly Spring field which seems to be doing pretty well. The Goodyear Gatorback is suppose to be good as well.
Had the same problem I changed plugs, wires,both coil packs, egr, o2 sensors ,mass air-flow sensor ,cleaned carbon from throttle body and intake manifold. Everything made the car drive better but it would still act up. Had the valve seals done and belt replaced and it went away for a week. Then had mechanic check it he cleaned the idle air control valve but he says I need a new one the car is a taxi and I haven't had time to put the new part. My car has 308,000 mile on an original engine only major work has been the valve seals so no complaints here and it is a P74 model
It most likely is a leak of some sort in the air intake. Mine did that when the air hose or any part of it would slip off. Anytime air gets in on the backside of the MAF sensor without going through it, thats what it'll do.The bigger the leak the bigger the problem.
Also check the Throttle Position Sensor($55) and you mentioned the coils ($40+each) all of which could be the problem. Without seeing the car in person, it could be any of these things. It's a process of elimination,GOOD LUCK!!!
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