wildazme

i had my plastic intake manifold replaced with the upgraded manifold and now my car is running funny. the car seems to have a slight miss or something under hard throttle. you can hear a gurgling type sound from the exhaust when getting on the gas and also the car feels as if its loosing some power. you can feel a hesitation. the work that was done on the car was the manifold being replaced and also my spark plugs were changed to motorcraft platinums. any ideas what can be wrong?

wildazme

?

99gtstang

air pocket

ackuric

intake manifold may have a leak, spray carb cleaner around the intake, just a lil, and see if you can locate a leak by seeing any increase in rpm's from just spraying. did you do this yourself or a shop. could be incorrectly gapped plugs.

may be a leak elsewhere too, cai or plenum, make sure everything is tight, and all hoses are connected.

getting any codes? how long have you driven it w/ this problem (wonderin if long enough to throw a code)

wildazme

i only drove it for about 15 minutes, after i got it from the shop. ill check all the hoses again in the morning. it seems like sometimes the problem goes away but then comes back again

wildazme

called the shop today and the mechanic said that the new intake needs a break in period, also said it might be that i needed some new wires, said they werent in the greatest condition., Anyway i bought some motorcraft wires and will install them most likely tomorrow. My other ? is do motorcraft spark plugs have to be gapped before installation? I could have sworn you had to gap them before installing but the mechanic says they were pregapped.

46blueStang

it could be a number of things, one possiblity is that you might need some stuff recalibrated, its not uncommon, i used to work in a speed shop and cars would come in after adding aftermarket parts and run bad
the increased airflow changes the engines settings, the engine itself is programmed for all the stock parts, and sometimes the computer cannot compensate for it, happend to me on my 5.0, i got it recalibrated and it ran fine,
or another possiblity is that there is a air pocket or leak , once agian very common. and for the spark plugs i would double check the gap ,sometimes they do and i have had once that were not, just check, good luck

DROES99STANG

I just wanted to say PRE-GAPPED means nothing. half the time they are not right on the money, and this could be whats making your car run rough. I installed pre-gapped spark plugs before and i didnt check them because I lost my Gap gauge and I just trusted the pre gap and my car was running real rough and sounding like it wanted to stall. So double check the Gap or better yet make the mechanic thats what you payed him for. I have never heard of a mechanic putting on pre gaps without checking them first. they are only accurately gapped probly 90% of the time. ok good luck

wildazme

thanks for the info again, i just disconnected the battery and im gonna try runningthe car and see if it helps. as for the air pocket how would i check for that? when i got the car the reservoir was empty and i added about another gallon of antifreeze. i have to wait for monday to check back with mechanic.

jmmorgan82

I've never heard of a "intake manifold break-in period". I did mine myself and it ran just fine after I swapped it and changed plugs.