Stumble/backfire?

Nixon1 · 08-10-2003, 12:05 PM

Ok...the past few days, when I'm cruising in 3rd gear (automatic tranny) at part throttle, around 2200 rpms, the car feels like it's giving me small little backfires here and there....I'm thinking that could be an exhaust leak maybe. When I let off the gas sometimes after being hard on the throttle, it backfires loudly. And also, at cruise at the same rpms mentioned before...every now and then the car will misfire and stumble a few times, or all of a sudden feel like it lags back...like when you engage the A/C compressor and the car feels slower and it takes slightly more gas to keep it at the same speed. What could be causing that? My old EGR valve was frozen up completely, so I have a brand new one now. Also, the TPS, IAC, and CTS are brand new, as well as the plugwires, cap and rotor, and ignition coil. Spark plugs have only been in for about a month but I havent had the chance to yank them and check color. Thanks all.

bottlebaby91 · 08-11-2003, 01:06 AM

check to make sure all plug wires are on tight, and what kind of plug wires do you have? Also check timing and adjust it and than drive it and see what it does, feels like.

Coupe50h · 08-11-2003, 02:48 AM

worst case scenario: Bent valve or pushrod.

08-10-2003, 12:05 PM	#1
Nixon1 Registered Member Join Date: Jan 2003 Location: Palm Bay, FL Posts: 432	Stumble/backfire? Ok...the past few days, when I'm cruising in 3rd gear (automatic tranny) at part throttle, around 2200 rpms, the car feels like it's giving me small little backfires here and there....I'm thinking that could be an exhaust leak maybe. When I let off the gas sometimes after being hard on the throttle, it backfires loudly. And also, at cruise at the same rpms mentioned before...every now and then the car will misfire and stumble a few times, or all of a sudden feel like it lags back...like when you engage the A/C compressor and the car feels slower and it takes slightly more gas to keep it at the same speed. What could be causing that? My old EGR valve was frozen up completely, so I have a brand new one now. Also, the TPS, IAC, and CTS are brand new, as well as the plugwires, cap and rotor, and ignition coil. Spark plugs have only been in for about a month but I havent had the chance to yank them and check color. Thanks all. __________________ '91 Mustang GT 5.0 AOD Daily Driver Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI 13.73 at 103.8, ~2.2 60'

08-11-2003, 02:48 AM	#3
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	worst case scenario: Bent valve or pushrod. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

08-11-2003, 01:06 AM	#2
bottlebaby91 Registered Member Join Date: Nov 2002 Posts: 141	check to make sure all plug wires are on tight, and what kind of plug wires do you have? Also check timing and adjust it and than drive it and see what it does, feels like.