fff

Hi,

I seem to have developed a problem with the car as of yesterday. I was merging on to 29 at about 35 MPH in 3rd gear. Jumped on the throttle to get up to speed and it sounded like someone was firing a machine gun. 15-20 loud backfires in rapid succession. Let off the throttle (apx 4k rpm), shifted to 4th and it felt like I was trying to leave a traffic light in 5th gear. I limped it to the mall parking lot, shut down for about 30 minutes. When I started it up I scared many people with an incredibly loud backfire. Backfired again when leaving the mall lot. Fast forward to this morning. Car is idling fine on cold and warm starts and mostly every traffic light. Under load it is surging, sputtering and way down on power (4k in 3rd = 35mph). I did not take it above 4k rpm, but even at 4k, it feels like the engine is struggling. At one light this morning it started idling as though there was a T-Rex in there(I am stock internally). The whole car was shaking. I feathered the throttle and it went away. Below 2k rpm, it runs great. The fuel filter was changed 2500 miles ago and the plugs have 8000 miles (Bosch Platinum Plus) on them. No SES lights are on and other than the struggle under load, the car is running normally. 93 or 94 octane is all I run. Any ideas?

As always,

Thanks!

Fred

Assassin

iTrader: (3)

sounds like its only runnin on a few cylinders, can you smell gas out of the exhaust at idle?, any ses light?, could be a broken spark plug, split plug wires, bad ground, off crank or cam sensor, could have run lean and blew a hole in a piston...could be alot of things but usually the ses light would come on before you even noticed anything...........get back w/ some answers

fff

I can smell gas at idle, but it has been that way since the headers and ory. It is no worse or better now. No SES lights. It was dynotuned after the header install (January) and the AFR was good. I don't have the sheet to post, but we spent an hour getting it right. I did a visual on all of the plug wires and all are on and tight. Is it possible to burn through a 02 sensor wire, have it cause this and not set an SES? That is one thing I forgot to check. As for the running on less than 8 cylinders, with no load on the engine and revving, it is just as strong as ever and with the exception of one traffic light, it idles just as smoothly as always. The problems don't start until the engine is under load.

Thanks!

glen

iTrader: (1)

Ck plugs, fuel filter, fuel pressure, coil breaking down, crank sensor

mike02ss

Check to make sure you didn't suck up something somehow into the airlid and check the maf while you're at it. Had a friend who had the same problem and he had sucked up a plastic bag somehow and it was making it's way into the maf.. Hope you find it soon.

fff

Well, I replaced the fuel filter and it made no difference. I have new plugs and wires on the way from Thunder, so that will be tonights project. I did check the intake path and it is clear from the lid through to the manifold. I'll post up tomorrow after the plug and wire swap. Thanks for all the help!

Fred