98 studdering possible vacuum leak
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98 studdering possible vacuum leak
Hi, I have a 98Expy with the 5.4L. I recently replaced some vacuum lines because it was causing the truck to stall and idle rough. Everything was great but now about 2 weeks later it is doing it again. I climbed under the hood and rechecked everything. Looks good. Check engine light is on but I haven;t had a chance to scan it yet. While under the hood I took off the cover to the throttle body and revved it so I could listen. When it first starts to rev it sounds like the engine is sucking air in the rear of the engine on the passenger side. I tried the aerosol trick to no avail. Is there any vacuums in the region that are hard to get to or know to be trouble some?
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If the codes are the lean codes then I went through the same thing with mine. I replaced the vac lines and elbow - they were cracked but not leaking and also changed the fuel filter. It was better for awhile then started again while on the road. Long story short - the road mechanic tested the MAF sensor and it passed, then I brought it home to my regular mechanic and he tested it with 2 different systems and it passed. After trying various things he took my truck to Ford and tested it there and the MAF failed. After a new one was put in it ran like new.
If you have a friend with the same motor or MAF sensor I would swap it out and try it just to be sure.
If you have a friend with the same motor or MAF sensor I would swap it out and try it just to be sure.
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